Stepless automatic variable transmission

ABSTRACT

A stepless automatic variable transmission with gears in a state of constant meshing which is operational without the need for disengaging or changing the gears such that the rotational output power can be varied to effect a neutral, low speed, medium speed, high speed, overdrive or reverse rotation by selecting a stepless automatic speed change method or a manual speed change method, and which includes a speed change system, an overdrive system and a speed change controlling system. The assembly of speed change system (10, 110, 310, 410, 510, 610), the overdrive system (50, 360, 660, 760) and the speed change controlling system (80, 180, 380, 680, 780) can vary with each of the systems combined to result in numerous stepless automatic variable transmissions. To effect speed changes low speed, medium speed, overdrive, and reverse rotation brake means are used. Also, either the manual speed change method or the automatic speed change method can be selected.

This is a divisional of application Ser. No. 08/166,921, filed Dec. 10,1993 now abandoned U.S. Pat. No. 5,415,592, which application areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an automatic transmission, and moreparticularly, to a stepless automatic variable transmission assembled insuch a way that power input to an input shaft can be converted andtransmitted to an output shaft without changing or disengaging gearswhen accelerating or changing speed to initiate and maintain forwardmotion and when reversing the rotational direction of the output shaftto initiate and maintain a backward motion.

2. Information Disclosure Statement

In the conventional manual transmission, speed changes are accomplishedby constantly choosing among different given gear ratios in accordancewith the load. Such constant attention is annoying in that the gearsmust always be disengaged and/or engaged at the time of a desired ornecessary speed change. Also, the existing automatic transmissions andbelt type stepless automatic transmissions are complicated in design andstructure and require a large dedicated installation area. Furthermore,such transmissions are expensive to manufacture.

The above problems are addressed in U.S. Pat. No. 5,062,823 which issuedon Nov. 5, 1991. However the transmission described therein requires aseparate means for reverse rotation of the output shaft thereby severelyrestricting the versatility of the transmission.

Other transmissions which have solved the problem of initiating andmaintaining a backward or reverse motion include: U.S. patentapplication Ser. Nos. 07/903,137 (filed 1992.Jun. 23), now U.S. Pat. No.5,326,334, 07/920,892 (filed 1992. Jul. 28), now U.S. Pat. No.5,322,488, 07/921,050 (filed 1992. Jul. 28), now U.S. Pat. No. 5,330,395and 08/028,824 (filed 1993. Mar. 10), now U.S. Pat. No. 5,364,320.

However, the present invention uses a design and construction of a speedchange system which is different from the above described systems andincludes an overdrive function which increases the rotational speed ofthe output shaft over the rotational speed input by the engine, or thelike. A speed change controlling system in which the speed can beadjusted steplessly and automatically is also utilized in the presentinvention.

Therefore, the objects of the present invention are to provide astepless automatic variable transmission which can solve the abovedescribed problems which have yet to be efficiently and effectivelysolved in the prior art.

Another object of the present invention is to provide a transmissionwhich is not as complicated as those of the prior art, includes a veryreliable speed change operation, has smooth rotational output, quicklyadapts to a change in the load and which includes overdrive and reverseoperations.

Another object of the present invention is to provide a continuousvariable automatic transmission which efficiently transmits rotationaloutput in either rotational direction and which is simple to constructand easy to maintain.

The preceding objects should be construed as merely presenting the morepertinent features and applications of the invention. Many otherbeneficial results can be obtained by applying the disclosed inventionin a different manner or modifying the invention within the scope of thedisclosure. Accordingly, other objects and a fuller understanding of theinvention may be had by referring to both the summary of the inventionand the detailed description, below, which describe the preferredembodiment in addition to the scope of the invention defined by theclaims considered in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

The stepless automatic variable transmission of the present invention isdefined by the claims with specific embodiments shown in the attacheddrawings. For the purpose of summarizing the invention, the inventionrelates to a stepless automatic variable transmission comprising a speedchange system which receives rotational power generated by a gasolineengine, or the like, and changes the rotational speed and transmits thepower to an output shaft. An overdrive system increases the ratio of thedrive shaft to the engine speed and a speed change controlling systemautomatically controls the rotational ratio in accordance with the loadof the output shaft. The stepless automatic variable transmissionenables input rotational force to be steplessly changed from the lowestto a predetermined ratio and transmitted to the output shaft.

According to the first embodiment of the present invention, the speedchange system includes an input sun gear for receiving rotational powergenerated by an engine, input differential gears meshed with the inputsun gear, control differential gears integrally formed with the inputdifferential gears, locking pins and carriers for operativelypositioning the differential gears. A medium speed ring gear, preferablyhaving a tube shaft boss, is meshed with the outside of the inputdifferential gears so as to control only the medium speed driving, ifnecessary. A control sun gear is integrally formed with a speed changecontrol shaft and is meshed with the inside of the control differentialgears so as to control the reverse rotation driving or a steplessautomatic speed change. An output ring gear is integrally formed with aring gear shaft and is meshed with the outside of the outputdifferential gears. The above elements constitute a compositedifferential gear set. A modification of the composite differential gearset further includes a support shaft and a support plate integrallyconnected to a stator.

The overdrive system includes a ring gear shaft for receiving the outputrotation from a speed change system, a carrier integral with the ringgear shaft, planetary gears for transmitting the rotation of thecarrier, locking pins and another carrier for operatively positioningthe planetary gears about the overdrive sun gear. The overdrive sun gearis integrally formed with an overdrive control shaft and is meshed withthe inside of the planetary gears. A terminal ring gear, integrallyformed with an output shaft, is meshed with the outside of the planetarygears, and constitutes a planetary gear set with an electromagneticclutch to enable the planetary gear set to rotate as a unit duringnormal operation, i.e. the overdrive function not enabled.

The speed change controlling system utilizes a torque converter of thetype used in conventional automatic transmissions but with changes inorder for it to function in the present invention. This systemcomprises, with reference to the elements used in a conventional torqueconverter for the convenience of explanation, an impeller which is thedriving body, a turbine which is the driven body, a stator forincreasing the torque, and a housing for containing the circulatingfluid. That is, the speed change controlling system comprises animpeller which rotates integrally with the input shaft, a turbine havinga fluid inlet formed on the middle part of the impeller for suction offluid and which is integrally connected to the speed change controlshaft of the speed change system, a stator installed between theimpeller and the turbine, a support shaft integrally formed with thestator, a support plate integrally formed with the support shaft androtating in the same direction as the two carriers of the speed changesystem, and an housing provided with a fluid inlet and a fluid outlet toallow circulation of the fluid therethrough. The housing is securedagainst rotation. In positioning the elements, preferably, the impelleris installed near the engine, the turbine is installed near the speedchange system, the stator is installed between the impeller and theturbine, and the housing is completely filled (100%) with fluid.

Generally, there are three methods of operation for the steplessautomatic variable transmission constructed as described above.

First, operation of the stepless automatic speed change to attain a verysmooth, quiet and efficient performance under typical drivingconditions.

Second, operation with a fixed speed change ratio to attain an enginebraking effect when operating in a mountainous area or on an icy road orwhen rapid starting is desired.

Third, operation to attain a combination of the above two methods.

It is a characteristic and advantage of the present invention that thethree methods of operation can be performed by the stepless automaticvariable transmission as described herein.

Reviewing the operation of the speed change system, when the outputshaft is stationary, the rotational input power rotates the medium speedring gear and the input differential gears in a rotational directionopposite to the input direction. The output differential gears, whichrotate in the same direction as the input direction, causes the carriersto rotate in a direction opposite to the input direction due to thestopped output ring gear. This results in a neutral state. Next, if thecarriers, which are idling in a direction opposite to the inputdirection, are completely stopped by applying a brake force through alow speed brake means installed on the tube shaft boss, the rotation ofthe output shaft is gradually increased in proportion to the brake forceapplied. "Idle" or "idling" in the present invention means that no workis being performed but the "idling" components may be rotating. Totransmit the power of the driving shaft to the output shaft at a mediumspeed, if the medium speed ring gear is stopped by applying a brakeforce through a medium speed brake means installed on the tube shaftboss, the output shaft rotates to a predetermined fixed gear ratio. Totransmit the power of the driving shaft at a high speed, the speedchange controlling system is connected to the speed change system. Thus,the resulting rotation of the impeller forces fluid to strike the bladesof the turbine such that a rotational force is transmitted to theturbine. That is, because the turbine, the speed: change control shaftand the control sun gear are integrally connected, the control sun gearis rotated by the rotation of the impeller which is the driving body. Atthis time, the speed change controlling system, the speed change systemand the overdrive system together form a rotating body which is in ahigh speed state. That is, the number of revolutions of the output shaftand the number of revolutions of the input shaft becomes equal.

In order to transmit the power to the output shaft in a overdrive state,the rotation of the overdrive sun gear is completely stopped byreleasing the electromagnetic clutch which integrally connects theterminal ring gear and the carrier of the overdrive system and therotation of the overdrive control shaft is completely stopped byapplying a rotational braking force to the overdrive control shaft, viathe overdrive brake means. These actions cause the output shaft torotate at a greater number of revolutions than the input shaft.

To reverse the rotation of the output shaft, i.e. reverse drivingmethod, when the terminal ring gear and the carrier of the overdrivesystem are rotating as a unit, i.e. not in an overdrive state, arotational braking force is applied through the reverse rotation brakemeans to stop the rotation of the speed change control shaft and thecontrol sun gear resulting in the output shaft rotating in a directionopposite to the rotational direction of the input shaft. This operationis initiated from the neutral state.

According to another embodiment (third embodiment) of the presentinvention, the speed change system includes an input sun gear forreceiving driving power generated by an engine. Input differential gearsare meshed with the input sun gear and control differential gears aremeshed with the input differential gears. The medium speed differentialgears are integrally formed with the control differential gears. Lockingpins and carriers are used to operatively position each differentialgear. An output ring gear, integrally formed with a ring gear shaft, ismeshed with the outside of the input differential gears. A control sungear is meshed with the inside of the control differential gears so asto control the low speed driving or stepless automatic speed change. Amedium speed sun gear is meshed with the inside of the medium speeddifferential gears so as to control only the medium speed driving ifdesired. Each of the above two sun gears is integrally formed on acontrol shaft, respectively.

The overdrive system includes a link gear integrally formed with thering gear shaft of the speed change system and receiving the power froma source of rotational output such as an engine, speed control system,or the like. Overdrive gears are integrally formed on a transmittingshaft so as to overdrive the rotation of the link gear up to apredetermined ratio. A fixed plate operatively positions the overdrivegears to mesh with the link gear and also operatively positions thetransmitting gears to mesh with the output gear of the output shaft.

The speed change controlling system utilizes a conventional torqueconverter as used in present day automatic transmissions. This systemcomprises, with reference to the elements used in a conventional torqueconverter for the convenience of explanation, an impeller which is thedriving body, a turbine which is the driven body and a stator forincreasing the torque all of which are operatively positioned in a coverwhich contains the circulating fluid.

Explaining the construction detail, a speed change controlling system iscomposed of a cover for preventing fluid in the converter from leakingout and rotating integrally with the input shaft, an impeller integrallyformed with the cover, a turbine integrally connected to the controlshaft of the speed change system, a fixed plate fixable on the outside,and a fixed shaft and a stator integrally formed with the fixed plate.In general, the turbine is installed near the engine, the impeller isinstalled near the speed change system, and the spacing between theturbine and impeller and the amount of fluid are similar to theconventional converter.

Reviewing the process of speed change, when the output shaft isstationary due to the load, the power input rotates the carriers in adirection which is the same as the input direction of rotation androtates the control sun gear and the medium speed sun gear in adirection opposite to the input direction, so that the output shaft doesnot rotate and the carriers, the control sun gear and the medium speedsun gear idle to be in neutral state. If the control sun gear iscompletely stopped by applying the brake force through a low speed brakemeans installed on the control shaft which is idling in a directionopposite to the input shaft, the rotation of the output shaft isincreased gradually proportionally to the brake force. To transmit thepower of the driving shaft to the output shaft in a medium speed, if themedium speed sun gear is stopped by applying the brake force through amedium speed brake means installed on the medium speed control shaft,the output shaft is rotated up to a given gear ratio. To transmit theoutput in a high speed, if the engine speed is gradually increased, therotational force of the impeller draws out the fluid and the fluidstrikes the blades of the turbine, so that the control shaft integrallyconnected to the turbine is rotated at the rotating speed of theimpeller, and at this time, the speed change controlling system and thespeed change system together form a rotating body to transmit the powerat a high speed. For the reverse rotation driving method, a brake forceis applied to the carriers through a reverse rotation brake meansinstalled on the tube shaft boss of the carrier causing the carriers tostop and resulting in the output shaft rotating in a direction oppositeto that of the input shaft.

In yet another embodiment (fifth embodiment) of the present invention,the speed change system utilizes an input sun gear receiving the drivingpower generated by an engine, planetary gears meshed with the input sungear, locking pins and carriers for operatively positioning theplanetary gears, and an output ring gear integrally formed with anoutput shaft and meshed with the outside of the planetary gears.

The speed change controlling system includes, with reference to theelements used in a conventional torque converter for the convenience ofexplanation, an impeller, turbine, stator which are operatively enclosedin a housing as described elsewhere.

Reviewing the operation between the speed change system and the speedchange controlling system, the impeller is rotated by the input shaft,the stator, for increasing the rotational force of the impeller, issecured to the fixed shaft, and the turbine, capable of adjusting thecarriers of the speed change system by receiving the rotational force ofthe impeller, is connected to the speed change control shaft.

The operation of the present stepless automatic variable transmission isas follows: when the output shaft is in a stationary state due to a loadplaced thereon, the rotational power input from an engine is dividedinto two paths, so that the power passed through the impeller makes thecarriers idle in a direction which is the same rotational direction asthe input sun gear direction. The power passed through the input sungear makes planetary gears only idle in a direction opposite to theinput direction to be in a neutral state. When forward motion isdesired, if the speed of the engine is increased, then the speed of theimpeller is increased, and therefore the force of the discharged fluidis increased, so that the revolution of the turbine gradually increasefrom the neutral state in which the turbine slips and the output shaftis rotated to initiate forward movement. To further increase the speed,if the speed of the engine is further increased, the operation isperformed with a revolution corresponding to the load of the outputshaft.

To initiate reverse rotation of the output shaft, if the brake force isapplied through a reverse rotation brake means installed on the speedchange control shaft, the carriers are stopped, and accordingly thepower rotates the output shaft in a direction opposite to the inputshaft.

According to yet another embodiment (sixth embodiment) of the presentinvention, a speed change system includes an input sun gear receiving adriving power generated at an engine, input planetary gears meshed withthe input sun gear, reverse rotation planetary gears being integrallyformed at the front of the input planetary gears for receiving thereverse rotation driving or the controlled speed change, outputplanetary gears integrally formed at the near of the input planetarygears, locking pins and carriers for operatively positioning the input,the reverse rotation, and the output planetary gears, a reverse rotationsun gear being integrally formed with a speed change shaft and beingmeshed with the inside of the reverse rotation planetary gears so as totransmit the reverse rotation driving and the controlled rotation, andan output sun gear being integrally formed with an output shaft andbeing meshed with the inside of the output planetary gears, andconstitutes one composite planetary gear set.

An overdrive system includes an input carrier receiving rotational powergenerated by an engine, overdrive planetary gears transmitting therotation of the input carrier, locking pins and another carrier foroperatively positioning the overdrive planetary gears, a control sungear being integrally formed with the control shaft which receives thecontrolled rotation and being meshed with the inside of the overdriveplanetary gears, and a control ring gear being meshed with the outsideof the overdrive planetary gears and transmitting the number ofrevolution which is higher than that of input rotation and thecontrolled number of revolution, and constitutes one planetary gear set.

Another speed change control system utilizes the principle of action andreaction and uses control blades and a control plate with resistanceblades secured to the internal surface of the housing which, inoperation, results in the application of rotational resistance to thecontrol blades.

Reviewing the operating methods of the stepless automatic variabletransmission constructed as described above, when the output shaft is instationary state due to a load, the input power rotates the carriers ofthe speed change system in a direction opposite to the input directionand also rotates the control sun gear of the overdrive system in adirection same as the input direction, so that the output shaft is notrotated and the carriers of the speed change system and the control sungear of the overdrive system are only idling in a neutral state. And ifthe carriers are completely stopped by applying the brake force througha forward rotation brake means installed on the carrier of the speedchange system which is idling in a direction opposite to the inputdirection, the revolution of the output shaft is increased up to therevolution corresponding to the fixed ratio corresponding to a teethratio proportionally to the brake force, and thereafter the controlblades of the speed change controlling system automatically control therevolutions to maintain the equilibrium according to the inputrotational force and the load on the output shaft and gradually transmitit to the output shaft. In the overdrive state, the control shaft isstopped by applying the brake force through an overdrive brake meansinstalled on the control shaft causing the rotation output of the outputshaft to further increase relative to that of the input shaft. Forreverse rotation driving, the brake force is applied via a reverserotation brake means installed on the speed change shaft causing thereverse rotation sun gear to stop and rotating the output shaft in adirection opposite to the input shaft.

As described above, the power generated by the engine can be easily andeffectively changed into neutral and forward or reverse rotationaloperation without disengaging or re-engaging gears and transmitted tothe output shaft. The structures according to the present invention arevery simple to use, economical to produce and operate.

The more pertinent and important features of the present invention havebeen outlined above in order that the detailed description of theinvention which follows will be better under stood and that the presentcontribution to the art can be fully appreciated. Additional features ofthe invention described hereinafter form the subject of the claims ofthe invention. Those skilled in the art can appreciate that theconception and the specific embodiment disclosed herein may be readilyutilized as a basis for modifying or designing other structures forcarrying out the same purposes of the present invention. Further, thoseskilled in the art can realize that such equivalent constructions do notdepart from the spirit and scope of the invention as set forth in theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

For fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconjunction with the accompanying drawings in which:

FIGS. 1-8 illustrate the first embodiment of the stepless automaticvariable transmission according to the present invention;

FIG. 1 is a partial perspective view of the first embodiment of thepresent invention;

FIG. 2 is a sectional view of the first embodiment according to thepresent invention;

FIG. 3 is a sectional view of the first embodiment in the neutral stateaccording to the present invention;

FIG. 4 is a sectional view of the first embodiment in the low speedstate with the carriers in a stopped position according to the presentinvention;

FIG. 5 is a sectional view of first embodiment in the medium speed statewith the medium speed ring gear in a stopped position according to thepresent invention;

FIG. 6 is a sectional view of the first embodiment in the high speedstate with the rotation ratio of the output shaft to the input shaftbeing 1:1 according to the present invention;

FIG. 7 is a sectional view of the first embodiment in the overdrivestate according to the present invention;

FIG. 8 is a sectional view of the first embodiment with the output shaftrotating in a direction opposite to that of the input shaft according tothe present invention;

FIG. 9 is a sectional view of the second embodiment of the steplessautomatic variable transmission according to the present invention;

FIG. 10-16 illustrate the third embodiment of the stepless automaticvariable transmission according to the present invention;

FIG. 10 is a partial perspective view of the third embodiment accordingto the present invention;

FIG. 11 is a sectional view of the third embodiment;

FIG. 12 is a sectional view showing third embodiment neutral stateaccording to the present invention;

FIG. 13 is a sectional view showing the stepless automatic variabletransmission of the third embodiment in the low speed state with thecontrol sun gear in a stopped position according to the presentinvention;

FIG. 14 is a sectional view showing the third embodiment in a mediumspeed state with the medium speed sun gear in a stopped positionaccording to the present invention;

FIG. 15 is a sectional view showing the third embodiment in a high speedstate according to the present invention;

FIG. 16 is a sectional view showing the third embodiment with the outputshaft rotating in a direction opposite to the input shaft according tothe present invention;

FIGS. 17-22 illustrate the fourth embodiment of the stepless automaticvariable transmission according to the present invention;

FIG. 17 is a sectional view of the fourth embodiment according to thepresent invention;

FIG. 18 is a sectional view showing the fourth embodiment in the neutralstate;

FIG. 19 is a sectional view showing the fourth embodiment in a low speedstate according to the present invention;

FIG. 20 is a sectional view showing the fourth embodiment in a mediumspeed state according to the present invention;

FIG. 21 is a sectional view showing the fourth embodiment in a highspeed state according to the present invention;

FIG. 22 is a sectional view showing the fourth embodiment with theoutput shaft rotating in a direction opposite to that of the input shaftaccording to the present invention;

FIGS. 23-26 illustrate the fifth embodiment of the stepless automaticvariable transmission according to the present invention;

FIG. 23 is an assembled sectional view of the fifth embodiment accordingto the present invention;

FIG. 24 is a sectional view showing the fifth embodiment the neutralstate according to the present invention;

FIG. 25 is a sectional view of the fifth embodiment in the forwardrotation driving state according to the present invention;

FIG. 26 is a sectional view of the fifth embodiment in the reverse stateaccording to the present invention;

FIGS. 27-32 illustrate the sixth embodiment of the stepless automaticvariable transmission according to the present invention;

FIG. 27 is a partial perspective view of the sixth embodiment accordingto the present invention;

FIG. 28 is a sectional view of the sixth embodiment in the according tothe present invention;

FIG. 29 is a sectional view of the sixth embodiment in the neutral stateaccording to the present invention;

FIG. 30A is a sectional view of the sixth embodiment in the forwardrotation driving state according to the present invention;

FIG. 30B is a sectional view of the sixth embodiment in the forwardspeed increasing state according to the present invention;

FIG. 31 is a sectional view of the sixth embodiment in the overdrivestate according to the present invention;

FIG. 32 is a sectional view of the sixth embodiment in the reversestate;

FIGS. 33-38 illustrates the seventh embodiment of the step lessautomatic variable transmission according to the present invention;

FIG. 35 is a partial perspective view of the seventh embodimentaccording to the present invention;

FIG. 34 is a sectional view of the seventh embodiment according to thepresent invention;

FIG. 35 is a sectional view of the seventh embodiment in the neutralstate according to the present invention;

FIG.36A is a sectional view of the seventh embodiment in the forwardrotation driving state according to the present invention;

FIG. 36B is a sectional view of the seventh embodiment in the forwardspeed increasing state according to the present invention;

FIG. 37 is a sectional view of the seventh embodiment in the overdrivestate according to the present invention; and

FIG. 38 is a sectional view of the seventh embodiment in the reversestate according to the present invention;

Similar reference characters refer to similar parts through out theseveral views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The stepless automatic variable transmission of the present inventionpreferably includes the speed change system, overdrive system and speedchange controlling system as a functional unit. From the teachings inthe present disclosure the speed change system, overdrive system andspeed change controlling system can be varied in their respectiveconstruction and can be combined together to define a stepless automaticvariable transmissions of various embodiments as appreciated by oneskilled in the art. Although the brake means, as illustrated in thedrawings, are installed on a control shaft and/or a tube shaft boss, theactual positions of the brake means and the construction thereof can bechanged. Also, the bearings or splines and splined hub can besubstituted by other elements which have same function. In general,operation of the speed change system in a "fixed ratio" means that theoutput is determined by the characteristics of the gears, e.g. number toteeth, comprising the speed change system.

A description of the first embodiment of the stepless automatic variabletransmission 1 of the present invention combines the speed change system10, overdrive system 50 and speed change controlling system 80 withreference to FIGS. 1-8 follows.

Speed change system 10

FIGS. 1 and 2 illustrate the input shaft 12 for inputting the rotationaldriving force of an engine into the transmission according to thepresent invention. The input shaft 12 consists of a first section 12A, asecond section 12B and a terminal end 12C with the input sun gear 14integrally formed on the input shaft 12. The support shaft 16 isrotatably and coaxially positioned on the first section 12A of the inputshaft 12 and is spaced apart from the input sun gear 14. At end 16A ofthe support shaft 16 splines 16S are formed to receive the coaxialsplined hub 18S of the disk shaped support plate 18. The stator 86 ofthe speed change controlling system 80 is secured to end 16A' of thesupport shaft 16 to enable simultaneous rotation with the support shaft.Bushings 86B, 86B', or the like, are used to permit the input shaft 12and the support shaft 16 to rotate independently. The speed changecontrol shaft 20 is coaxially and rotatably positioned on the supportshaft 16 with a control sun gear 22 formed at end 20A of the speedchange control shaft 20. To enable simultaneous rotation splines 88S areformed at the opposite end 20A' of the speed change control shaft 20which engage the splined hub 88S' of turbine 88 of the speed changecontrolling system 80. Bushings 88B, 88B', or the like, are used so thatthe support shaft 16 and the speed change control shaft 20 can rotateindependently.

Next, the carrier 26 having a tube shaft boss 24 is rotatably positionedon the speed change control shaft 20 proximate the control sun gear 22.Bearings 26B, 26B', or the like, are used to permit the speed changecontrol shaft 20 and the carrier 26 to independently rotate. The carrier28 is positioned at the terminal end 12C of the input shaft 12 with abearing 28B to permit the terminal end 12C of the input shaft and thecarrier 28 to rotate independently. The medium speed ring gear 44 havinga tube shaft boss 42, is coaxially and rotatably positioned on the tubeshaft boss 24 with a bearing 44B to permit the medium speed ring gear 44and the carrier 26 to rotate independently.

In order that the two carriers 26, 28 can rotate together, a pluralityof locking pins 30, 32 is used to interlink and secure the two carriers26, 28 together, as see FIG. 1.

An input differential gear 34AA, of the plurality of input differentialgears 34, and a control differential gear 36AA, of the plurality ofcontrol differential gears 36, which may be integrally formed, arerotatably positioned on each locking pin 30A. The input differentialgear 34AA and the control differential gear 36AA are of different sizesand are spaced apart 34A a predetermined distance. Bearings 34B, 34B',or the like, are used to promote rotation about the locking pin. Theinput sun gear 14 is meshed with the inner side of the forward half ofthe input differential gear 34AA. The medium speed ring gear 44 ismeshed with the outer side of the forward half of the input differentialgear 34AA, and the control differential gear 36AA is meshed with thecontrol sun gear 22. A spacing ring 40 may be inserted onto the lockingpin 30A at the rear side of the input differential gear 34AA to preventaxial movement of the composite differential gears 34AA, 36AA along thelocking pin 30A during use.

On the other hand, the output differential gear 38A, of the plurality ofoutput differential gears 38, is rotatably mounted on locking pin 32A byusing, for example, bearings 38B, 38B'. The forward half of the outputdifferential gear 38A is meshed with the rear half of the inputdifferential gear 34AA, and on the outer side of rear half of the outputdifferential gear 38A is meshed the output ring gear 46. The output ringgear 46 has an axial bore 48 formed therein and is integrally formedwith a ring gear shaft 52 along its axis. Bearing 48B is insertedbetween the bore 48 and the terminal end 12C of the input shaft topermit the output ring gear 46 to rotate thereabout. In a similar mannerring 40' can be used to prevent the axial movement of the outputdifferential gear 38A during use.

The support plate 18 is integrally connected to the stator 86 of thespeed change controlling system 80. Holes 18A, 18A' are formed in thesupport plate 18 in order to rotatably receive each of the locking pins,respectively, as illustrated at FIG. 2. Bearing 18B may be used topromote independent rotation of the support plate about the lockingpins.

Locking pin 30A, input differential gear 34AA, control differential gear36AA and ring 40 together make a set and similarly locking pin 32A,output differential gear 38A and ring 40' make a set. For balance androtational stability two of each set are used. However, as appreciatedby those skilled in the art, there is no limit in the number of setsused.

The differential gear set of the present speed change system 10, asdescribed above, efficiently changes the engine torque to provide abroad range of power output. Also, since the gears of the presentinvention are always in a meshed state, the transmission of presentinvention can absorb large amounts of shock and exert a greaterrotational force during operation.

Overdrive system 50

When the overdrive system is operatively connected to the speed changesystem 10, the ring gear shaft 52 is used. Since the purpose of the ringgear shaft 52 is to receive rotational input from a rotational outputsource such as an electric motor or a gearbox driven by an internalcombustion engine, it may be considered as an input shaft of theoverdrive system.

As described above, the ring gear shaft 52 includes a first section 52Aand a terminal end 52B. The overdrive control shaft 54, with anoverdrive sun gear 56 secured at end 54A, is rotatably and coaxiallypositioned on the ring gear shaft 52. Bearings 56B, 56B', or the like,are used to permit independent rotation of the ring gear shaft 52 andthe overdrive control shaft 54. The carrier 60 with a tube shaft boss 58is rotatably positioned on the overdrive control shaft 54. Bearings 60B,60B', or the like, are used to permit independent rotation of thecarrier 60 and the overdrive control shaft 54. The carrier 62 includes acoaxial splined hub 62S which receives splines 52S formed on the ringgear shaft 52 to secure the carrier 62 and the ring gear shaft 52together, as illustrated at FIG. 2. A plurality of locking pins 64 areused. Each locking pin 64A interlinks and secures carriers 60, 62together so that the carriers 60, 62 rotate simultaneously.

Each planetary gear 68A, of the plurality of planetary gears 68, isrotatably positioned on each locking pin 64A via a bearing 68B, or thelike, to ensure independent rotation and is meshed with the overdrivesun gear 56. The terminal ring gear 74 includes an axial bore 70 formedtherein to rotatably receive the terminal end 52B of the ring gear shaft52. The terminal ring gear 74 meshes with the outside of each planetarygear 68A and terminates in the output shaft 72. The bearing 74B, or thelike, is inserted between the bore 70 and the ring gear shaft to ensurethat the terminal ring gear 74 rotates freely about the ring gear shaft52.

A conventional mechanical clutch or electromagnetic clutch 98 isinstalled between the tube shaft boss 58 of the carrier 60 and theterminal ring gear 74 to connect or release the carrier 60 and terminalring gear 74 so that the planetary gear sets of the overdrive system 50can be made to rotate as a unit.

Although the terminal ring gear 74 is described as being connected to orreleased from the carrier 60 by utilizing the electromagnetic clutch 98,the same function may be performed when the overdrive control shaft 54is connected to or released from the carrier 60 by other conventionalmeans.

Speed change controlling system 80

The speed change controlling system 80 utilizes a conventional torqueconverter as presently used in automatic transmissions. Accordingly, adetailed description thereof is omitted, and a description of only thatportion which has been modified and improved so as to adapt it for usein the present invention with the speed change system 10 is presented.

The torque converter as conventionally used functions as a fluid clutchwhich transmits and amplifies torque to the gears of the transmission.

However, in the present invention the principal power is directlytransmitted to the input sun gear 14 via the input shaft 12, asdescribed above. The role of the speed change controlling system 80 inthe present invention is to make the rotational force of the turbinecontrol only the rotation of the control sun gear 22. To achieve this,the positions of the impeller and the turbine are opposite to that ofthe conventional torque converter and with the stator being rotated bycarriers 26, 28 of the speed change system 10. Furthermore, the methodof circulation of the fluid, such as transmission fluid or the like, isa natural circulation method, i.e., operation without a pump. The speedchange controlling system 80 uses an incision type torque converter anda fixed housing 90 while the conventional torque converter is a closedtype.

The impeller 84 is coaxially secured to the first section 12A of theinput shaft 12 by using, for example, a splined hub 84S which mesheswith the splines 12S formed on the input shaft so that the impeller 84rotates simultaneously with the input shaft 82. An optimum number offluid inlets 82 are formed in the central portion of the impeller 84 forsucking the fluid. The stator 86 is integrally formed with the supportshaft 16 which is rotatably and coaxially installed on the input shaft12. Bushings 86B, 86B' are used, for example, to permit the input shaft12 and the support shaft 16 to independently rotate. To rotatably securethe speed change control shaft and the turbine together, the speedchange control shaft 20 includes splines 88S formed at end 20A' toreceive the coaxial splined hub 88S' of the turbine 88 to enable theturbine 88 to rotate simultaneously with the speed change control shaft20.

At the time of installation, the impeller 84 and the turbine 88 areinstalled facing each other in such a manner so as to be spaced apart byonly a very small distance but sufficiently apart to permit rotationwithout direct mechanical engagement, i.e. contact. Stator 86 ispositioned between the impeller 84 and the turbine 88, with the stator86 rotating in the same direction as the carriers 26, 28 of the speedchange system 10.

The housing 90 for containing the necessary circulating fluid ispositioned along the first section 12A of the input shaft 12 and thespeed change control shaft 20. The fluid inlet 91 with passageway 91Afor suction of fluid naturally circulating from the outside is formed inone side 90A of the housing near the impeller 84. The fluid outlet 92with a passageway 92A is formed in the top of the housing and bearings90B, 90B', or the like, are used so that the input shaft 12 and thespeed change control shaft 20 can independently rotate. Fluid-seals 90C,90C' are used to prevent leakage of the fluid contained in the housing.The housing 90 is secured against rotation by an outer fixing means,i.e. secured to a non-rotatable structure, such as an automobile frame,by a weld, bolt etc.

The characteristics of the speed change controlling system 80constructed as described above is that the rotation of the speed changecontrol shaft 20 of the speed change system 10 can be smoothly andrapidly controlled to obtain the optimum speed change ratio inaccordance with the load.

To obtain maximum engine braking effect or when rapid starting isrequired, a conventional clutch 99 is positioned at "C" of the speedchange control shaft 20 to control the rotation of the control sun gear22 of the speed change system 10 and the speed change controlling system80 by uncoupling the rotation of the turbine, as see FIG. 2. Thisdriving mode is a speed change interval where a fixed speed change ratiois required from the starting low speed to the medium speed, thereforethe above described speed change controlling system 80 is not used andseparate mechanisms, i.e. brake means, are used.

The method for changing the speed in this way requires brake means 93,94, 96 positioned in the speed change system 10 for changing the speedat each step, and to operate at a fixed speed change ratio by applying abrake force from the outside. That is, the low speed brake means 93,which further includes a oneway bearing, is positioned on the tube shaftboss 24 to permit only rotation in one direction. When activated, thelow speed brake means 93 stops the carriers 26, 28 when starting orrapidly starting. The medium speed brake means 94 is installed on thetube shaft boss 42 to control the medium speed ring gear 44 in themedium speed state by stopping the rotation of the gear 44. The reversespeed brake means 96 is installed on the speed change control shaft 20to control the control sun gear 22 when reverse rotation of the outputshaft relative to the rotation of the input shaft is desired.

The low speed, medium speed and reverse brake means as used in thepresent invention can utilize either automatic control or manual controland electric, electromagnetic, hydraulic, pneumatic or frictional means.One example of a brake means, as illustrated in the figures, is a meansto force a brake lining to inhibit and control rotation against aportion of the surface of the carriers 26, 28 to initiate and achievelow speed, the medium speed ring gear 44 to achieve medium speed, andthe speed change control shaft 20 to achieve reverse rotation. Asappreciated by those skilled in the art other brake means well known inthe art could be used and would be expected to accomplish the intendedbraking purpose.

For the low speed brake means 93, a conventional one-way bearing can beused to restrain only the reverse rotation of the carriers 26, 28 thusgetting rid of an inconvenience that after the brake force is applied atthe time of speed change, the brake force has to be released again.

In the present embodiment, a conventional torque converter is improvedto function in the speed change controlling system 80 of the presentinvention. That is, other such devices as fluid coupling, electric,electromagnetic and powder clutches and powder coupling can be used. Asillustrated, the turbine 88 is connected to the speed change controlshaft 20 for speed change control. However, it can also be connected tothe carriers 26, 28 or the medium speed ring gear 44 for speed changecontrol to attain the intended purpose, and [his does not limit thescope of the present invention.

The power transmission process and the speed change status of thepresent embodiment as described above are explained below whileoperating in neutral, low speed, medium speed, high speed, overdrive andreverse rotation states.

The transmission of the present invention may be used with anyrotational power means and in any mechanism which requires that thepower output be varied to accommodate varying loads. Thus, the presentinvention may be used in combination with automobiles, trucks andindustrial machines, etc.

For purposes of illustration, the continuously variable transmission ofthe present invention is described in combination with an automobile.Further, the bushings or splines can be substituted by other elementswhich have the same function and are well known in the art.

In the figures the direction of rotation when viewed from the left sideof each figure of the input shaft is counterclockwise, and is indicatedas "↑" or "A" and the direction opposite to the input shaft, i.e.clockwise, is indicated as "↓" or "B".

The following description is applicable to other embodiments of thepresent invention as well. The rotation of each differential geardefines rotation about its own axis, i.e. a locking pin. Whereas, arevolution defines a revolution by a carrier about the axis of the inputshaft. Whether there is an increase or decrease in the number ofrotations or revolutions in a particular state is determined relative tothe number of rotations or revolutions relative to the neutral state.

Here the rotational force of the input shaft 12 is divided into twopaths. In one path the rotational force is transmitted to the impeller84 of the speed change controlling system 80, the stepless automaticspeed change method. In the other path the rotational force istransmitted to the input sun gear 14 of the speed change system 10, themethod in which driving can be performed at a fixed speed change ratioto obtain rapid starting or a maximum engine braking effect.

The low speed, medium speed and reverse rotation states which utilize afixed speed change ratio are described first. Then the high speed andoverdrive states are described.

I-1. Neutral state (FIG. 3): Output ring gear 46 and overdrive system 50are stopped ##STR1##

The neutral state is a state in which the driving force of the engine isnot output to the output shaft 72 and the transmission idles as shown inFIG. 3. That is, where rotational force is input to the driving shaft ofthe engine where a load is applied to the output shaft 72, the inputshaft 12 and the input sun gear 14 rotate in the same direction "A". Asthe input sun gear 14 rotates, the input differential gear 34AA meshedwith the input sun gear 14 rotates about the locking pin 30A indirection "B". Accordingly, the control differential gear 36AA, theinput differential gear 34AA, and the medium speed ring gear 44 rotate(that is, idling) in the direction "B", and the control sun gear 22meshed with the control differential gear 36AA rotates (idling) indirection "A" which is the same as the input shaft 12.

The output differential gear 38A meshed with the input differential gear34AA rotates in the direction "A", however, because the output ring gear46 meshed with the output differential gear 38A is in the stationarystate due to the load, the output differential gear 38A rotates aboutits own axis and at the same time revolves around the inside of theoutput ring gear 46, and therefore the carriers 26, 28 rotate (idling)in the direction "B".

Due to the rotation of the carriers 26, 28 in direction "B", eachdifferential gear rotates and revolves in the direction as describedabove.

In this state, the rotational force which passes through the input shaft12 cannot rotate the output shaft 72 which is stationary due to the loadwhich inhibits rotation. Thus, the rotational input renders the controlsun gear 22, the medium speed ring gear 44 and the carriers 26, 28 idleso as to be in neutral state, i.e. dissipate the rotational force input.

I-2. Low speed state (FIG. 4): Until the carriers 26, 28 are stopped.

When operating the speed change system 10, i.e. driving at a fixed ratioin the low speed state, medium speed state or reverse speed state, byusing the brake means, the rotation of the turbine can be separated fromthe speed change system 10 by utilizing the clutch 99 on the "C" portionof the above described speed change control shaft 20. Therefore, anexplanation of the operation condition of the speed change controllingsystem 80 is omitted.

During normal operation, the electromagnetic clutch 98 of the overdrivesystem 50 connects the terminal ring gear 74 and the carrier 60 suchthat the entire overdrive system 50 rotates as a unit, and therefore,the number of revolutions and the rotational direction are respectivelythe same for the output ring gear 46 and the output shaft 72. However,this rotational equivalence is not present during the overdrive state.

Input shaft 12↑--Input sun gear 14↑--Input differential gears34AA↓--Output differential gears 38A↑--Output ring gear 46↑--Carriers60, 62↑ of the Overdrive system--Terminal ring gear 74 and Output shaft72↑.

In the low speed state the rotation of the output shaft 72 is graduallyincreased from the neutral state. By applying a brake force P1 to thecarriers by the low speed brake means 93 installed on the tube shaftboss 24 utilizing a one-way bearing which restrains the rotationaldirection, the rotation of the carriers 26, 28, which were rotating in adirection opposite to the rotation of the input shaft 12, graduallydecreases and stops, and accordingly the rotation of the output shaft 72is initiated and gradually increases in proportion to the rotationaldecrease of the carriers 26, 28.

That is, the rotation of the input differential gear 34AA and thecontrol differential gear 36AA about their respective axes in direction"B", decreases proportionally to the decrease in the rotation of thecarriers 26, 28 due to the application of the brake force P1, and theoutput differential gear 38A, meshed with the input differential gear34AA, rotates in direction "A", which is the same direction as the inputshaft rotation. At this time, the rotation of gear 38A about its ownaxis decreases relative to the neutral state, and then the output ringgear 46, meshed with the output differential gear 38A, rotates in thesame direction "A". When the carriers 26, 28 are in stationary state,the output ring gear 46 rotates according to the fixed speed changeratio of only the rotational force of the output differential gear 38Aabout its own axis, i.e. there is no revolutions about the axis of theinput shaft, since the carriers are stopped.

As the Output ring gear 46 rotates, the carriers 60, 62 of the overdrivesystem rotate in direction "A", which is the same as the direction ofthe output ring gear 46, through the ring gear shaft 52 which isintegrally formed with the output ring gear 46, and accordingly theterminal ring gear 74 and the output shaft 72 rotate in the samedirection. At this time, because two elements (the terminal ring gear 74and the carriers 60, 62) which can rotate independently as describedabove are connected to form an integral element, the overdrive system 50rotates as a unit.

The medium speed ring gear 44 and the control differential gear 36AArotate in direction "B", which is the same direction as the inputdifferential gear 34AA, with the rate of rotation decreasing relative tothe neutral state. For the control sun gear 22 which is rotating in thedirection "A", the rate of rotation is increasing.

I-3. Medium speed (FIG. 5): Until the medium speed ring gear 44 isstopped. ##STR2##

The medium speed state is used to increase the rotation of the outputshaft 72 above that of the low speed state. Here the brake force P2 isapplied by the medium speed brake means 94 installed on the tube shaftboss 42. This causes the rotation of the medium speed ring gear 44 whichwas rotating in direction "B", opposite to the input shaft 12, togradually decrease to a stop. That is, as the rotation of the mediumspeed ring gear 44 slows, the rotation of the input differential gear34AA about its own axis decreases as its revolutions around the insideof the medium speed ring gear 44 increases, and accordingly the carriers26, 28, which were stopped in the low speed state, rotate in direction"A".

At the same time, the revolutionary force of the output differentialgear 38A, meshed with the input differential gear 34AA, increases due tothe rotational force of the carriers 26, 28 in direction "A" and thereduction in the rotational force of the input differential gear 34AAabout its own axis.

Therefore, the output ring gear 46, meshed with the output differentialgear 38A, rotates in direction "A" by being further accelerated due tothe increase in the rotational force of the carriers 26, 28 and therevolutionary force of the output differential gear 38A. Carriers 60, 62of the overdrive system 50 integral with the output ring gear rotate atthe same rate and in direction "A", therefore the terminal ring gear 74and the output shaft 72 rotate in the same direction.

By comparison, the control differential gear 36AA rotates in direction"B" about its own axis at a lower rate relative to the low speed statewhile the number of revolutions with the carriers increases. The controlsun gear 22 rotates in direction "A" at a greater rate than in the lowspeed state.

Heretofore, the procedure of continuously varying the speed to low speedand medium speed and of transmitting the power to the output shaft 72has been described. These states are accomplished with the fixed speedchange ratio making for easy operation of the engine as a braking means.

I-4. Reverse rotation state (FIG. 8): Speed change control shaft 20 andcontrol sun gear 22 are stopped ##STR3##

In the reverse rotation state the output shaft 72 rotates in a directionopposite to the rotational direction of the input sun gear 14. Here thebrake force R1 is applied by the reverse rotation brake means 96installed on the speed change control shaft 20 to control sun gear 22.This causes the control sun gear 22 to gradually stop and the outputring gear 46 to rotate in the direction opposite to that of the inputsun gear 14.

That is, as the rotation of the control sun gear 22 gradually decreasesand stops because of the brake force R1, the rotations of the controldifferential gear 36AA about its axis and the number of its revolutionsabout the control sun gear 22 increase. Therefore, the rotations of thecarriers 26, 28 which rotate in direction "B" increase. At the sametime, the rotation and the revolutions of the input differential gear34AA, which is integral with the control differential gear 36AA, alsoincrease in direction "B".

The rotation of the output differential gear 38A, meshed with the inputdifferential gear 34AA, increases in direction "A" and its revolutionabout the axis of the input shaft increases in direction "B", togetherwith the carriers 26, 28. Therefore, the output ring gear 46, meshedwith the output differential gear 38A, rotates in direction "B" oppositeto the input sun gear 14.

At this time, because the influence of the rotational force of thecarriers 26, 28 rotating in direction "B" is greater than that therotational force of the output differential gear 38A rotating indirection "A", the output ring gear 46 rotates in direction "B", and theoverdrive system 50 rotates as a unit in direction "B" via carriers 60,62 of the overdrive system 50 integrally connected to the output ringgear 46.

By comparison, the rotation of each gear in the reverse rotation isincreased relative to the rate of rotation in the neutral state with theexception of the control sun gear 22.

Heretofore, the fixed speed change ratio which can obtain maximum enginebraking effect with only the operation of the speed change system 10,i.e. not engaging the control of the speed change controlling system 80by utilizing the conventional clutch 99 on the "C" portion of the speedchange control shaft 20 to couple system 80, is described above for thelow speed, medium speed, reverse rotation states, respectively.

An explanation follows concerning the method of operation and the stateof using the stepless automatic speed change system to obtain themaximum driving comfort and the most economical driving force bycontrolling the rotation of the control sun gear 22 via the speed changecontrol shaft 20 by coupling the speed change controlling system 80 andthe speed change system 10 via the clutch 99 installed at the "C"portion of the speed change control shaft 20 to engage the speed changecontrolling system 80.

The explanation of transmitting the power to the input sun gear 14 ofthe speed change system 10 is as it is described above.

I-A. Neutral state (FIG. 3) Input shaft 12↑--Impeller 84↑--Turbine88↑--Control sun gear 22↑--Control differential gears 36AA↓ (idling)

When the output shaft 72 is stationary due to the load, part of thedriving force of the engine rotates the impeller 84 of the speed changecontrolling system 80 via the input shaft 12 in the same direction "A"and at the same speed, and because the blades of the impeller 84 rotatetogether with the fluid, the fluid discharged from the blades strikesthe blades of the turbine 88 installed to face the impeller and therotational force transmitted as such tends to increase the rotation ofthe turbine 88 in the same direction "A". However, when the output shaft72 is stationary due to the load and the engine is idling at lowrevolutions per minute, the fluid discharged from the impeller 84 doesnot exert sufficient force to increase the rotation of the turbine 88,so that the turbine 88 slips.

In other words, reviewing the rotation of the turbine 88 which slips indirection "A", the turbine 88 is rotated not by the force of the fluiddischarged from the impeller 84 but by the influence (load) of thecontrol differential gear 36AA via the control sun gear 22 and the speedchange control shaft 20 since the clutch has coupled the shaft 20.

As described above, when the engine is idling at low revolutions perminute, the fluid discharged from the impeller 84 of the speed changecontrolling system 80 cannot exert a force capable of rotating theturbine 88 to control the rotation of the control differential gear36AA, so that the output shaft 72 remains in the stationary state.

I-B, Low speed state (FIG. 4): Until the carriers 26, 28 are stopped##STR4##

Since the low speed state is described in detail at "I-2", above, anexplanation is given only as to when the carriers 26, 28 are stopped andthe other state is not described for it is same as the state "I-2".

In the low speed state the rotation of the output shaft 72, which wasstopped in the neutral state, is gradually increased, and if therotational speed of the engine is gradually increased, the speed of theimpeller 84 increases. Thus, the force of the fluid discharged againstthe turbine 88 increases, with the result that the rotation of theturbine 88 gradually is initiated and increased from the slip state inthe neutral state. Consequently, the rotation of the output shaft 72gradually increases in proportion to the increase of the rotation of theturbine 88.

That is, if the force of the engine is increased from the state at whichthe turbine 88 slips, the force of the fluid discharged from theimpeller 84 increases, and the rotation of the turbine 88 rotating indirection "A" is increased up to a speed change point at which therotation of the turbine 88 and the load of the output shaft 72 are in astate of equilibrium. Therefore, the speed change control shaft 20 andthe control sun gear 22, integrally connected to the turbine 88, controlthe rotation of the control differential gear 36AA rotating in direction"B", and this control force gradually decreases the rotation of thecarriers 26, 28 rotating in direction "B" ultimately stopping thecarriers 26, 28.

The state in which the carriers 26, 28 are stopped as described above isthe same as the state in which the carriers 26, 28 are stopped byapplying the brake force P1 by the low speed brake means 93 as describedin detail in the state "I-2".

As described above, when part of the input power rotates the impeller 84of the speed change controlling system 80 which in turn results in therotation of the turbine 88 integral with the control sun gear 22, if theload of the output shaft 72 is larger than the input driving force, thenthe rotation of the control sun gear 22 is decreased, and if the load ofthe output shaft 72 is smaller than the input driving force, then therotation of the control sun gear 22 is increased, so that optimum speedchange ratios can be obtained to always reach equilibrium.

I-C. Medium speed state (FIG. 5): Until the medium speed ring gear 44 isstopped ##STR5##

Because the medium speed state is described in detail at "I-3", above,an explanation is given only until the medium speed ring gear 44 isstopped, and the remaining state is as described for state "I-3".

In the medium speed state the rotation of the output shaft 72 is furtherincreased from the low speed state. Thus, if the rotational speed of theengine is increased from the low speed state, the carriers 26, 28, whichwere stationary, now rotate in direction "A", the same as the inputshaft 12. Therefore the rotation of the medium speed ring gear 44, whichwas rotating in direction "B", decreases from the low speed state andstops.

The state in which the medium speed rig gear 44 is stopped as describedabove is the same as the state in which the medium speed ring gear 44 isstopped by applying the brake force P2 by the medium speed brake means94 as described in detail in the state "I-3".

The rotation of the output shaft 72 is increased in proportion to thereduction in the rotation of the medium speed ring gear 44 and therotational force of the carriers 26, 28. That is, the rotation of thecontrol sun gear 22 increases due to the increase in the rotationalforce of the turbine 88. Accordingly, the rotation of the controldifferential gear 36AA about its own axis decreases, while therevolutions of the carriers 26, 28 increase, and due to therevolutionary force, the rotation of the output differential gear 38A indirection "A" is also decreased, while the revolutions of the outputdifferential gear 38A increase, so that the rotation of the output ringgear 46 meshed with the output differential gear 38A accelerates.

I-D. High speed state (FIG. 6): Until the rotation ratio of the inputshaft and the output shaft becomes 1:1 ##STR6##

In the high speed state the rotational speed of the output shaft isaccelerated from the medium speed state. Here the rotational speed ofthe engine is further accelerated relative to the medium speed statecausing the medium speed ring gear 44, which was in a stationary state,to rotate in direction "A", for a while, and then the medium speed ringgear 44 rotates together with the input differential gear 34AA.

In this state, the rotational force of the input shaft 12 is dividedinto two paths. One path for transmitting the rotational force to theinput differential gear 34AA by rotating the input sun gear 14, theother path for transmitting the rotational force to the controldifferential gear 36AA by rotating the turbine 88 via the input shaft 12and the impeller 84 and at the same time by rotating the control sungear 22.

At this time, the force of the fluid discharged from the impeller 84increases due to the increase in the rotational speed of the engine.Accordingly, the turbine 88 slips a little against the impeller 84 for awhile to rotate at a speed change point corresponding to a runningresistance value and then the turbine 88 rotates at the same speed asthe impeller 84, and this rotation is input to the control differentialgear 36AA via the control sun gear 22. And rotational force is input tothe input differential gear 34AA via the input sun gear 14, that becausethe same rotational forces are applied to the two is, integral gears34AA, 36AA, they cannot rotate about their own axes but can only revolvetogether with the carriers 26, 28.

In this state, the total body (10) forms a rotating body with the twosun gears 14, 22 as a center so as to be rotated in direction "A", andbecause all the differential gears have no rotational force about theirown axes, further speed change points cannot be formed, and thereforethe rotational force of the engine directly drives the output shaft 72.

I-E. Overdrive state (FIG. 7): Until the overdrive sun gear 56 of theoverdrive system is stopped ##STR7##

In the overdrive state the output rotational speed is accelerated up toa predetermined gear ratio greater than the output rotational speed inthe high speed state. In operation, when the electromagnetic clutch 98of the overdrive system 50 is released during the above described highspeed state and the brake force P3 is applied by the overdrive brakemeans 95 installed on the overdrive control shaft 54, the overdrive sungear 56, which rotated in direction "A", stops. That is, as theoverdrive sun gear 56 stops, the planetary gears 68 rotate in direction"A" and at the same time revolve around the overdrive sun gear 56together with the carriers 60, 62. Therefore the terminal ring gear 74,meshed with the planetary gears 68, and the output shaft 72 are in anoverdrive condition and rotate according to the rotation of the carriers60, 62. The gear ratio is dependent according to the number of teeth ofthe planetary gears 68.

A description of the second embodiment of the stepless automaticvariable transmission of the present invention combines the speed changesystem 110, speed change controlling system 180 and overdrive system 50with reference to FIG. 9 follows.

The construction of the speed change system 110 in the steplessautomatic variable transmission 100 is the same as that of the speedchange system 10 of the first embodiment Accordingly, the referencenumerals for each of the illustrated elements are same as those of thespeed change system 10, However, in this embodiment the support shaft 16and the support plate 18 for fixing the stator 86 are removed. Inaddition, the operation method and the operation state of the speedchange system 110 of the second embodiment are same as for the speedchange system 10 of the first embodiment, therefore a descriptionthereof is omitted. Also the construction of the overdrive system 50 isthe same as that of the first embodiment, and therefore a description ofthe overdrive system 50 is omitted.

The construction of the speed change controlling system 180 of thesecond embodiment is the one to which the speed change controllingsystem 80 is applied. However, the relative positions of the impeller 84and the turbine 88 are changed. Nevertheless, the operation method andthe operation state in which the speed is changed steplessly andautomatically are same as for the first embodiment. Therefore a detaileddescription thereof is omitted, and only the construction of the speedchange controlling system 180 is presented.

Speed change controlling system 180

The speed change controlling system 180 utilizes a torque converter ofthe automatic transmission, which is a well known apparatus. However,the conventional device is modified so as to perform in the presentinvention. Accordingly, a detailed description thereof is omitted, and adescription of only that portion which has been modified and improved soas to adapt it for use in the present invention with the speed changesystem 110 is presented.

As described above, the rotational force of the turbine 188 is only forcontrolling the rotation of the control sun gear 22, and the method ofcirculating the fluid is a natural circulation type, i.e. not requiringa pump. A fixed housing 190 is used to contain the fluid forcirculation.

As shown in FIG. 9, a cover 181 is secured to the first section 12A ofthe input shaft 12, the input shaft 12 passes through the middle of thecover 181, a spline hub 181S is coaxially formed in the cover 181 whichmeshes with the splines 12S formed in the input shaft 12 so that thecover 181 can be rotated integrally with the input shaft 12. The cover181 is connected to the impeller 184 by a weld or a dog clutch at theperiphery of the cover 181 so that the cover rotates integrally with theimpeller 184. An optimum number of fluid outlets 183 are formed on theperiphery of the cover 181 to permit the flow of fluid therethrough.

To secure the turbine 188 to the end 20A' of the speed change controlshaft 20 splines 188S are formed on the speed change control shaft 20 toreceive the coaxial splined hub 188S' formed in the turbine 188 toenable the turbine 188 and the speed change control shaft 20 to rotatesimultaneously. Bushings 188B, 188B' are used to ensure that the inputshaft 12 independently rotates relative to the speed change controlshaft 20 coaxially positioned thereon.

At the time of installation, the impeller 184 and the turbine 188 areinstalled facing each other in such a manner so as to be spaced apartonly a very small distance but sufficiently apart to permit rotationwithout direct mechanical engagement, i.e. contact. This distance isthat conventionally used in this device. A stator 186 is positionedbetween the impeller 184 and the turbine 188 and secured to a one-waybearing 185 having a coaxial formed splined hub 185S for receiving thesplines 187S formed on the hollow fixed shaft 187.

Bushings 187B, 187B' are used to ensure that the speed change controlshaft 20 rotates independently relative to the hollow fixed shaft 187. Abearing 184B secures the fixed shaft 187 to the impeller 184 to permitindependent rotation of the impeller 184. A fluid inlet 191 in fluidcommunication with a fluid passageway 189 are formed in the fixed shaft187, with the fluid passageway 189 terminating between the stator 186and the impeller 184 to permit circulation of the fluid of the speedchange controlling system 180, as illustrated in FIG. 9.

The housing 190, for containing the fluid, is secured to the fixed shaft187 by means of a splined hub 190S formed therein which receives thesplines 187S' of the fixed shaft 187. The housing encloses the speedchange control system 180 and includes a fluid outlet 192 with apassageway 192A formed therein to enable fluid to pass therethrough. Abearing 190B is used so that the input shaft 12 can rotates freelywithin the housing 190. A fluid-seal 190C is also used to preventleakage of the fluid. The housing 190 is secured against rotation by anexternal fixing means.

A description of the third embodiment of the stepless automatic variabletransmission of the present invention combines the speed change system310, overdrive system 360 and speed change controlling system 380 withreference to FIGS. 10-16 follows.

Speed change system 310

The stepless automatic variable transmission 300 of the third embodimentof the present invention includes, as shown in FIGS. 10 and 11, an inputshaft 312 for receiving the rotational driving force from the drivingshaft of the engine. The input shaft 312 consists of a first section312A, a second section 312B and a terminal end 312C, with an input sungear 314 formed integrally on the input shaft 312 between the secondsection 312B and the terminal end 312C. The control shaft 316, with acontrol sun gear 318 formed at one end 316A' of the control shaft 316,is rotatably and coaxially mounted on the first section 312A of theinput shaft 312. Splines 316S are formed at end 316A of the controlshaft 316 to engage the coaxial splined hub 388S of the turbine 388 toenable the control shaft 316 to be rotated simultaneously with theturbine 388 of a speed change controlling system 380. Bearings 318B,318B' are used to ensure that the input shaft 312 and the control shaft316 can rotate independently. The medium speed control shaft 320 with amedium speed sun gear 322 formed at one end 320A of the medium speedcontrol shaft 320, is rotatably and coaxially positioned on the controlshaft 316. Bearings 322B, 322B' are used to ensure that the controlshaft 316 and the medium speed control shaft 320 can independentlyrotate.

The carrier 332 having a tube shaft boss 330 is rotatably positioned onthe medium speed control shaft 320 proximate the medium speed sun gear322 with a bearing 332B to ensure that the carrier 332 and the mediumspeed control shaft 320 can rotate independently. The carrier 334 ispositioned proximate the terminal end 312C of the input shaft 312.Bearing 334B ensures that the carrier 334 and the terminal end 312C canrotate independently. Each of the plurality of locking pins 336, 338interlink and secure the two carriers 332, 334 together to ensure thatboth the carriers 332, 334 rotate simultaneously, as see FIG. 10. Aplurality of input differential gears 340, control differential gears344 and medium speed differential gears are used.

Each input differential gear 340G of the plurality of input differentialgears 340 is coaxially positioned on a locking pin 336P with bearings340B, 340B' to ensure independent rotation about the locking pin. Theinner side of the rear half of each input differential gear 340G ismeshed with the input sun gear 314. A spacing ring 342, or the like, maybe positioned on the locking pin to prevent axial movement of the inputdifferential gear 340G, as see FIG. 11.

The control differential gears 344G and the medium speed differentialgears 346G are of different sizes, respectively, and are spaced apart344A a predetermined distance on locking pin 338P, as see FIG. 11.Differential gears 344G, 346G are rotatably positioned on each lockingpin 338P via bearings 344B, 346B to ensure independent rotation of thegears 344G, 346G about the locking pin 338P. The rear half of eachcontrol differential gear 344G of the plurality of control differentialgears 344 is meshed with the forward half of one of the inputdifferential gears 340G of the plurality of input differential gears340, respectively. The inner side of each forward half of each controldifferential gear 344G is meshed with the control sun gear 318. Eachmedium speed differential gear 346G is meshed with the medium speed sungear 322. The spacing ring 348 prevents axial movement of the compositedifferential gears 344G, 346G.

Here, locking pin 336P, input differential gear 340G and spacing ring342, or the like, form a set. Likewise, locking pin 338P, controldifferential gear 344G, medium speed differential gear 346G and spacingring 348 form a set. Two of each such sets are preferably used to impartstability in the body during rotation. However, as is appreciated bythose skilled in the art, there is no limitation as to the number ofsets.

The outer side of the rear half of the input differential gear 340G ismeshed the output ring gear 352 which terminates in a ring gear shaft354 which has an axial bore 350 formed therein to rotatably receive theterminal end 312C of the input shaft 312. Bearing 350B is positionedbetween the bore 350 and the terminal end 312C of the input shaft toensure that the output ring gear 352 can rotate thereabout.

Overdrive system 360

The output ring gear 352 includes an axially positioned ring gear shaft354 with the ring gear shaft 354 terminating in a link gear 358. Thelink gear 358 transmits rotational output from the speed change system310 to the overdrive system 360 and further includes an axial bore 356formed therein. The axial bore 356 rotatably receives the first end 362Aof the plate shaft 362.

The plate shaft 362 includes a fixed plate 364 coaxially formed thereonwith the plate shaft having a first end 362A and a second end 362A'.Holes 365, 365A are formed in the fixed plate 364. A bearing 358B ispositioned into the axial bore 356 of the link gear 358 to ensure thatthe link gear 358 rotates freely about the first end 362A of [he plateshaft 362.

A plurality of overdrive gears 368 and transmitting gears 370 are usedin the overdrive system. Each overdrive gear 368G is integrally formedwith each transmitting shaft 366G of a plurality of transmitting shafts366 with the overdrive gear thereof meshed with the link gear 358, assee FIG. 11. Each hole 365, 365A formed in the fixed plate 364 securelyand rotatably receives the transmitting shaft 366G therethrough, toenable the transmitting shaft 366G to rotate within each respectivehole, such that each overdrive gear meshes with the link gear 358. Afterbeing rotatably and securely mounted on the fixed plate 364, atransmitting gear 370G is secured thereto. Each transmitting shaft 366Gincludes splines 366S formed thereon to engage the coaxial splined hub370S of the transmitting gear 370G to ensure simultaneous rotation withthe transmitting shaft. A stop ring 372, or the like, is used to securethe transmitting gear 370G to the transmitting shaft 366G. A bearing366B is positioned in each hole 365, 365A of the fixed plate 364 toensure that each transmitting shaft 366G rotates freely within therespective hole 365, 365A.

The output shaft 376 includes an output gear 378 with an axial bore 374formed therein to rotatably receive the second end 362A' of the plateshaft 362 to ensure that the output shaft rotates freely about the plateshaft. The output gear 378 is meshed with each transmitting gear 370G. Abearing 374B is positioned into the axial bore 374 of the output gear378 to ensure that the output shaft 376 rotates freely about the secondend 362A' of the plate shaft 362. The fixed plate is secured againstrotation, as see FIG. 11.

Here again, a transmitting shaft 366G, an overdrive gear 368G and atransmitting gear 370G together form a set, and, for reason of stabilitytwo sets are used. However, there is no limitation to the number of suchset, as appreciated by those skilled in the art.

Speed change controlling system 380

The speed change controlling system 380 utilizes a conventional torqueconverter as presently used in automatic transmissions. Accordingly, adetailed description thereof is omitted, and a description of only thatwhich has been modified and improved so as to adapt it for use in thepresent invention with the speed change system 310 is discussed herein.

Splines 312S are formed on the first section 312A of the input shaft 312to engage the coaxial splined hub 382S of the disk shaped cover 382 toensure that the disk shaped cover 382 rotates simultaneously with theinput shaft 312. A fluid-seal 384C' is installed on the input shaft 312proximate the splined hub 382S of the disk shaped cover 382 to preventloss of fluid therefrom. The disk shaped cover 382 further includes aninternal surface 384A with a plurality of impeller blades 384 securedthereto, by any suitable means such as welding, to enable simultaneousrotation with the disk shaped cover 382. The disk shaped cover 382 isrotatably secured to the fixed shaft 390 and fully encloses the impeller384, turbine 388 and stator 386, as see FIG. 11. Bearing 384B is used toensure that the disk shaped cover 382 freely rotates about the fixedshaft 390, and the impellers 384 mounted to the interior surface of thehousing. Fluid-seals 384C are positioned proximate the bearings 384B toprevent the loss of fluid from the disk shaped cover 382.

The turbine 388 includes a coaxial splined hub 388S formed therein toengage the splines 316S formed on the control shaft 316 which iscoaxially and rotatably mounted on the input shaft 312 to ensuresimultaneous rotation of the control shaft 316 and the turbine 388 aboutthe input shaft 312. The impeller 384 and the turbine 388 are positionedfacing each other in such a manner so as to be spaced apart by only avery small distance, yet sufficiently apart to permit rotation withoutdirect mechanical engagement, i.e. contact, as see FIG. 11.

The fixed shaft 390 is coaxially and rotatably positioned on the controlshaft 316 and includes a fixed plate 392 mounted thereon and which issecured to prevent rotation of the fixed shaft 390. The stator 386 ispositioned between the impeller 384 and the turbine 388 and mounted on aone-way bearing 386'. The one-way bearing includes a coaxial splined hub386S formed therein to engage the splines 390S of the fixed shaft 390 tosecure the one-way bearing 386' against rotation about the fixed shaft390, i.e. to permit the one-way bearing to enable rotation in a singledirection. Bearings 390B, 390B' are used to ensure that the controlshaft 316 rotates freely within the fixed shaft 390. Fluid inlet andoutlet passageways 394P, 395P, respectively, are formed in the fixedshaft 390, with each of the fluid passageways terminating between thestator 386 and the impeller 384 to permit, in use, circulation of thefluid of the speed change controlling system 380, as see FIG. 11. Fluidpassageways 394P, 395P each include an inlet 394 and outlet 395,respectively.

The speed change controlling system 380 constructed as described aboveis characterized in that a speed change point can be obtained where apart of the power of the engine controls the rotation of the turbine 388through the impeller 384, that is, the driving force of the engine andthe drive resistance of the output shaft 376 can always be in a state ofequilibrium.

A modification may be made in the event rapid starting or increasedengine braking is desired by adding to the speed change controllingsystem a means to selectably control, in use, the rotation of thecontrol sun gear 318 of the speed change system 310.

In one example, the control shaft 316 is cut or severed to form a firstcontrol shaft 316F and a second control shaft 316G with a clutch 399functionally positioned therebetween to control the rotation of thecontrol sun gear 318 of the speed change system 310, i.e. to enable theengagement and disengagement of the speed controlling system 380.Referring to FIG. 11, a clutch 399 would be installed where the controlshaft 316 has been severed, i.e. at point "C"' of the control shaft 316,to permit engagement and disengagement as desired. Another way toachieve this would be not use either the splines 312S formed on thefirst section 312A of the input shaft 312 or the coaxial splined hub382S of the disk shaped cover 382 thereby permitting the disk shapedcover 382 and the control sun gear 318 to rotate freely and install aclutch 399 at "D" to permit engagement and disengagement as desired ofthe input shaft and the cover.

Because the driving mode using the speed change system and its brakemeans, as described above, is a speed interval where the fixed speedchange ratio is needed from the low speed to the medium speed, the speedchange controlling system 380 is not used. That is, to change the speedas described above, brake means are operatively positioned at certainlocations in the speed change system 310, as see FIGS. 13-16, andactivated to change the speed. The fixed speed change ratio results byapplying a brake force. That is, the low speed brake means 396, using aone-way bearing which restrains the direction of rotation, is installedon the control shaft 316 to stop the control sun gear 318 when rapidstarting is desired. A medium speed brake means 397 is installed on themedium speed control shaft 320 to control the medium speed sun gear 322when medium speed is desired. A reverse rotation brake means 398 isinstalled on the tube shaft boss 330 to stop the carriers 332, 334 whenreverse rotation of the output shaft is desired.

The braking method used in this embodiment is the same as that describedfor the first embodiment.

It is a characteristic of the present embodiment that the fixed speedchange ratio can be obtained with a speed change controlling system 380and a speed change system 310. Further, the stepless automatic speedchange method of the present invention automatically selects new speedchange ratios to constantly maintain a state of equilibrium inaccordance with the driving force of the engine and the load of theoutput shaft 376 which varies continuously.

A description of the operation to achieve a speed change state accordingto the third embodiment follows for the neutral, low, medium, high andreverse rotation states, respectively.

The rotational force input passes through the input shaft 312 and isdivided into two paths. In one path (stepless automatic speed change)the rotational force is transmitted to the impeller 384 of the speedchange controlling system 380. In the other path (fixed speed change)the rotational force is transmitted to the input sun gear 314 of thespeed change system 310. The low speed, medium speed and reverserotation states which need a fixed speed change ratio are describedfirst followed by a description of the high speed states is given in thestate where the speed is changed steplessly and automatically.

Because the rotation of the turbine 388 may be disconnected by using theclutch 399 at "C'" on the control shaft 316 or at "D", for example,during operation with only fixed speed change ratio, a description ofthe operation status of the speed change controlling system 380 isomitted below.

II-1. Neutral state (FIG. 12): Output ring gear 352 is stopped ##STR8##

In the neutral state the driving force of the engine is not output tothe output shaft 376 and the transmission idles as shown at FIG. 12.That is, if the rotational force input from the driving shaft of theengine where a load is applied to the output shaft 376, the input shaft312 and the input sun gear 314 rotate in direction "A". As the input sungear 314 is rotated, each of the input differential gears 340G meshedwith the input sun gear 314 rotate about the locking pin 336P indirection "B", opposite to the rotational direction of the input sungear 314. Therefore, because the output ring gear 352, meshed with eachof the input differential gears 340G, is stationary due to the load,each input differential gear 340G rotates about its own axis and at thesame time revolves around the inside of the output ring gear 352 andtherefore carriers 332, 334 only idle in direction "A", and at the sametime, rotate the control differential gears 344 meshed with each of theinput differential gears 340G and each of the medium speed differentialgears 346G in direction "A". The control sun gear 318 (meshed with theplurality of control differential gears 344) and the medium speed sungear 322 (meshed with the plurality of medium speed differential gears346) idle in the direction "B". At this time, because the carriers 332,334 rotate in direction "A", each differential gear concurrently rotatesabout its own axis and revolves in the direction described above.

As described above, the rotational force input through the input shaft312 cannot rotate the output shaft 376 which is in stationary state dueto the load, with the result that only carriers 332, 334, the controlsun gear 318 and the medium speed sun gear 322 idle, which results inthe neutral state.

II-2. Low speed state (FIG. 13): Control sun gear 318 is stopped##STR9##

In the low speed state the rotation of the output shaft 376 is initiatedand gradually increases. Brake force Pal applied by the low speed brakemeans 396 installed on the control shaft 316 with a one-way bearingrestrains the rotational direction as described above. The rotation ofthe control sun gear 318 which was rotating in direction "B" now slowsto a stop, and therefore the rotation of the output shaft 376 graduallyincreases in proportion to the reduction of the rotation of the controlsun gear 318. That is, as the rotation of the control sun gear 318decreases due to the braking action of Pal, the rotation in direction"A" of the control differential gears 344 meshed with the control sungear 318 decreases. Therefore, the control differential gears 344, therotation of which is decreasing, controls the rotation of the inputdifferential gears 340, and the control force increases the rotation ofthe carriers 332, 334, which were rotating in direction "A", so as torotate faster than in the neutral state. As a result the output ringgear 352, which was stationary, now rotates in direction "A".

As the rotation of the carriers 332, 334 increases, the rotation of thedifferential gears about their respective axis decreases, while therevolutions together with the carriers 332, 334 increases. The mediumspeed sun gear 322 gradually rotates in direction "B" because therotational force about its own axis of the medium speed differentialgears 346 meshed with the medium speed sun gear 322 is relativelygreater than the revolutionary force of the medium speed differentialgears 346.

The overdrive system 360 increases the rotational output received fromthe speed change system 310 to a constant ratio.

As the output ring gear 352 rotates, the ring gear shaft 354 and thelink gear 358, integral with the output ring gear 352, rotate in thesame condition and rotate the overdrive gear 368 in direction "B" whichin turn can increase the rotation of the link gear 358 to a constantratio, and the rotation of the link gear rotates the output gear 378 andthe output shaft 376 in the same direction "A" as the input shaft 312via the transmitting gear 370.

II-3. Medium speed state (FIG. 14) ##STR10##

In the medium speed state the rotation of the output shaft 376 isfurther increased from the low speed state. The brake force Pa2 isapplied by the medium speed brake means 397 to the medium speed controlshaft 320. This causes the rotation of the medium speed sun gear 322,which was rotating in direction "B", to slow and stop. Therefore therotation of the output shaft 376 gradually increases in proportion tothe reduction of the rotation of the medium speed sun gear 322.

That is, the control differential gear 344 further controls the rotationof the input differential gear 340 by the brake force Pa2 as describedabove. This control force further increases the rotation of the carriers332, 334 in direction "A", therefore the rotation of the output ringgear 352 is further increased relative to the low speed state, and therotation of the output shaft 376 is also increased to the predeterminedratio.

As the rotation of the carriers 332, 334 increases, the rotation aboutthe respective axis of each differential gear is further decreasedrelative to the low speed state while the revolutions together with thecarriers 332, 334 increases. At this time, if the speed of the engine isincreased or the load of the output shaft 376 is decreased, the inputdifferential gear 340 stops rotating and only revolves together with thecarriers in direction "A".

The rotational direction of the control sun gear 318 which was rotatingin direction "B" changes to direction "A", because the revolutionaryforce of each control differential gear 344 gradually increases andbecomes greater than the rotational force about its own axis.

Here, since the rotational direction and the transmission procedure ofthe overdrive system 360 are same as for the low speed state, adescription thereof is omitted.

II-4. Reverse rotation state (FIG. 16) Input shaft 312↑--Input sun gear314↑--Input differential gears 340G↓--Output ring gear 352↓--Ring gearshaft 354 and Link gear 358↓--Overdrive gears 368G and Transmittinggears 370G↑--Output gear 378 and output shaft 376↓ (Opposite directionto the input shaft)

In the reverse rotation state the output shaft 376 rotates in adirection opposite to that of the input sun gear 314. When in neutral, abrake force Pa3 is applied by the reverse rotation brake means 398 tothe tube shaft boss 330 of the carrier 332. This results in thecarriers, which were rotating in direction "A", to slow and stop and theoutput ring gear 352 now rotates in a direction opposite to that of theinput sun gear 314.

That is, as the rotation of the carriers 332, 334, which were rotatingin direction "A" in the neutral state, is stopped by the brake forcePa3, the rotation each of the input differential gears 340 increases andtherefore the output ring gear 352 rotates in direction "B".

As the rotation of the input differential gears 340 increases, therotation of each of the control differential gears 344 and of the mediumspeed differential gears 346 rotating in direction "A" is increased.Likewise, rotation of the control sun gear 318 and the medium speed sungear 322 meshed with the control differential gears 344 and the mediumspeed differential gears 346, respectively, increases in direction "B"opposite to the input sun gear 314.

The input differential gear 340, which is rotating in direction "B", isfinally in a state where it has no revolutionary force since carriers332, 334 have stopped. In other words, because the influence of therotational force about its own axis is relatively large, the output ringgear 352 rotates in direction "B".

As stated above, this description is given about the fixed speed changeratio which can obtain the maximum engine braking effect by operatingonly the speed change system 310 and the brake means without using thespeed change controlling system 380 by utilizing the conventional clutch399 installed at, for example, "C'" on the control shaft 316 or at "D"as see FIG. 11, i.e. the basic neutral, low speed, medium speed andreverse rotation states.

A description of the method of operation and state of using the steplessautomatic speed change system to obtain the maximum driving comfort andthe most economical driving force by controlling the rotation of thecontrol sun gear 318 via the control shaft 316 by operating the speedchange controlling system 380 and the speed change system 310 by theclutch 399 installed at the "C'" portion of the control shaft 316 or "D"portion to operatively engage the speed change controlling system 380follows.

Since the reverse rotation state utilizing the fixed speed change ratiois same as the state "II-4" described above, a description thereof isomitted.

II-A. Neutral state (FIG. 12)

Input shaft 312↑--Impeller 384↑--Turbine 388↓--Control sun gear 318↓(idling)

When the output shaft 37.6 is stationary due to the load, because partof the driving force of the engine rotates the impeller 384 of the speedchange controlling system 380 via the input shaft 312 in the samedirection "A" and at the same speed and the blades of the impeller 384rotate together with the fluid, the force of the fluid discharged fromthe blades tends to control the rotation of the turbine 388, which isrotating in direction "B". However, when the output shaft 376 isstationary state due to the load and with the engine idling at lowrevolutions per minute (RPMs), the fluid discharged from the impeller384 cannot exert a force sufficient enough to control the rotation ofthe turbine 388, such that the turbine slips.

In other words, the turbine 388, which slips in direction "B", isrotated, not by the force of the fluid discharged from the impeller 384,but by the influence (load) of the control differential gears 344 viathe control sun gear 318 and the control shaft 316.

As described above, when the engine is idling at low revolutions, thefluid discharged by the impeller 384 cannot exert sufficient force whichcan control the rotation of the turbine 388 which is then beingcontrolled by the rotation of the control differential gears 344,resulting in the output shaft 376 remaining in a stationary state.

II-B. Low speed state (FIG. 13): Until the control sun gear 318 isstopped ##STR11##

Since the low speed state is described in detail at "II-2" above, adescription until the control sun gear 318 is stopped is presented heresince the omitted portion is the same as that described at "II-2".

In the low speed state the rotation of the output shaft 376, isinitiated and gradually increased. Thus, if the rotational speed of theengine is gradually increased from low revolutions, the rotational speedof the impeller 384 is increased. This causes the force of the fluidbeing discharged by the impeller to be increased which graduallycontrols the rotation of the turbine from the slip state. Therefore, therotation of the output shaft 376 gradually increases in proportion tothe reduction of rotational speed of the turbine 388 which was rotatingin direction "B".

That is, if the force (RPMs) of the engine is increased, the force ofthe fluid discharged from the impeller 384 is increased, and therotation of the turbine (which was rotating in the direction "B") isgradually decreased to a speed change point where the rotational forceof the turbine is in an equilibrium state with the load of the outputshaft 376 and is stopped. Therefore, the control sun gear 318 integralwith the turbine 388 controls, that is, decreases the rotation of thecontrol differential gears 344 which were rotating in the direction "A",and therefore the rotation of the input differential gears 340, whichwere rotating in the direction "B", is also decreased.

As described above, the state in which the control sun gear 318 isstopped is same as the state in which the control sun gear 318 isstopped in the state "II-2" by applying the brake force Pa1 by the abovedescribed low speed brake means 396.

In the same manner as described above, when part of the input powerrotates the impeller 384 of the speed change controlling system 380 andthe rotational force rotates the turbine 388 which is integral with thecontrol sun gear 318 via the force of the fluid, if the load of theoutput shaft 376 is larger than the input driving force, then therotation in direction "B" of the control sun gear 318 is increased inthe low speed state, and if the load of the output shaft 376 is smallerthan the input driving force, then the rotation in direction "B" of thecontrol sun gear 318 is decreased which results in obtaining an optimumspeed change ratio which always results in a state of equilibrium, i.e.the driving force input by the engine is equal to the load of the outputshaft, i.e. the total resistance to the motion.

II-C. Medium speed state (FIG. 14): Until the medium speed sun gear 322is stopped ##STR12##

A description of the action of the medium speed sun gear 322 until itstops is described below, thereafter the medium speed state is the sameas described in detail in the state "II-3".

In the medium speed state the rotation of the output shaft 376 isfurther increased over the low speed state, and if the rotational speedof the engine is further increased from that in the low speed state asdescribed above, the additional rotational force generated causes theturbine 388 and the control sun gear 318, which were in a stationarystate, to rotate in direction "A". Therefore the rotation of the inputdifferential gears 340 and the medium speed sun gear 322, which wererotating in direction "B", gradually decreases over that in the lowspeed state and finally stop.

The state in which the medium speed sun gear 322 is stopped is same asthe state in which the medium speed sun gear 322 is stopped in the state"II-3" by applying the brake force Pa2 by the above described mediumspeed brake means 397.

II-D. High speed state (FIG. 15): Until the rotation ratio of the inputshaft and the speed change system becomes 1:1 ##STR13##

In the high speed state the output rotational speed is furtheraccelerated over that of the medium speed state. Thus, when therotational speed of the engine is further increased over that of themedium speed state, the medium speed sun gear 322, which was in astationary state, rotates in direction "A" and finally rotates togetherwith the carriers 332, 334.

In this state, the rotational force passing through the input shaft 312is divided into two paths. In one path the rotational force istransmitted to the input differential gears 340 by rotating the inputsun gear 314 via the input shaft 312. In the other path the rotationalforce is transmitted to the control differential gears 344 by rotatingthe turbine 388 via the input shaft 312 and the impeller 384 and at thesame time rotating the control sun gear 318.

At this time, the force of the fluid discharged from the impeller 384due to the increase of the rotational output of the engine increases. Inresponse, the turbine 388 slips a little against the impeller 384 andfinally rotates at the same speed as the impeller 384 so as to berotated at a speed change point (this is the speed in the equilibriumstate) which corresponds to the driving resistance. This rotationalspeed is input to the control differential gears 344 via the control sungear 318, and another rotational force is input to the inputdifferential gears 340 via the input sun gear 314. That is, because thetwo differential gears 344, 340 integral with each other are given samerotational force, they cannot rotate about their respective axes but canonly revolve together with the carriers 332, 334.

In this state, the speed change control system 380 and the speed changesystem 310 rotate together as a unit about sun gears 314, 318 indirection "A". Also, because all the differential gears do not rotateabout their respective axes, no more new speed change point is formed,i.e. a state of equilibrium and therefore the state becomes one in whichthe ratio is 1:1 with the rotational force directly driving the outputring gear 352.

Next, the rotational output of output ring gear 352 is transmitted tothe link gear 358 of the overdrive system 360. This rotational output isfurther increased to a predetermined gear ratio as it passes through theoverdrive gear 368 and the transmitting gear 370. Therefore the rotationof the output gear 378 and the output shaft 376 is greater than therotation of the input shaft 312, i.e. the overdrive state.

A description of the fourth embodiment of the stepless automaticvariable transmission of the present invention combines the speed changesystem 410, speed change controlling system 380 and overdrive system 360with reference to FIGS. 17-22 follows.

The stepless automatic variable transmission 400 of the fourthembodiment utilizes the speed change controlling system 380 and theoverdrive system 360, as described in the third embodiment, togetherwith a speed change system 410. That is, the construction of the speedchange controlling system 380 and the overdrive system 360 as used inthe fourth embodiment is same as in the third embodiment. Therefore therespective method of operation and the functional role in the fourthembodiment is, as would be expected, the same as for the thirdembodiment. A detailed description of the speed change controllingsystem 380 and the overdrive system 360 is presented above.

The medium speed control shaft 320, medium speed sun gear 322, mediumspeed brake means 397 and the medium speed differential gears 346 whichare meshed with the medium speed sun gear 322 for medium speed drivingare removed from the speed change system 310 of the third embodiment toresult in the speed change system 410 of the fourth embodiment.

Referring to FIG. 17, the low speed brake means 496 for applying a brakeforce to the control shaft 316 in the fourth embodiment is the same asthe low speed brake means 396 of the third embodiment. The reverserotation brake means 498 is also the same as in the third embodiment.However, the reference numerals for the low speed brake means 496 andthe reverse rotation brake means 498 are different from those in thethird embodiment, with the reference numerals for the remaining partsbeing the same as in the third embodiment.

The power transmitting procedure and the speed change state of thefourth embodiment of the stepless automatic variable transmission of thepresent invention constructed as described above are same as for thethird embodiment and therefore are explained only briefly below.

III-A. Neutral state (FIG. 18) ##STR14##

In the neutral state, as shown in FIG. 18, there is no rotation of themedium speed differential gear 346 and the medium speed sun gear 322 inthe neutral state as shown in FIG. 12 of the third embodiment.

Since the state of other parts is similar to the third embodiment, thedescription thereof is omitted.

III-B. Low speed state (FIG. 19): Until the control sun gear 318 isstopped ##STR15##

For a discussion of the low speed state as shown in FIG. 19, refer tothe description of the low speed state "II-B" in the third embodimentwhich is equally applicable for the low speed state of this embodiment.##STR16##

For a discussion of the medium speed state as shown in FIG. 20, refer tothe description of the medium speed state "II-C" for the thirdembodiment, above, which is equally applicable for the medium speedstate of this embodiment.

III-D. High speed state (FIG. 21): Until the rotation ratio of the inputshaft and the speed change system becomes 1:1 ##STR17##

For a discussion of the high speed state as shown in FIG. 21, refer tothe description of the high speed state "II-D" for the third embodiment,above, which is equally applicable for this high speed state.

III-E. Reverse rotation state (FIG. 22)

Input shaft 312↑--Input sun gear 314↑--Input differential gears340G↓--Output ring gear 352↓--Ring gear shaft 354↓--Link gear358↓--Overdrive gears 368G↑--Transmitting gears 370G↑--Output gear378↓--Output shaft 376↓ (opposite direction to the input shaft) In thereverse rotation state the carriers 332, 334 are stopped by the reverserotation brake means 498 installed on the tube shaft boss 330 of thecarrier 332, and is similar to the reverse rotation state of FIG. 16 ofthe third embodiment, therefore the description hereat is omitted.

A description of the fifth embodiment of the stepless automatic variabletransmission of the present invention combines the speed change system510 and speed change controlling system with reference to FIGS. 23-26follows.

In the stepless automatic variable transmission 500 of the fifthembodiment of the present invention, the speed change controlling system550 is same as the speed change controlling system 180 as described forthe second embodiment and as illustrated at FIG. 9. The speed changesystem 510 utilizes a planetary gear set, and the variable transmissionis driven by only a stepless automatic speed change operating withoutthe need for a clutch. An overdrive system can be added, if desired.

Speed change system 510

The stepless automatic variable transmission 500 of the fifth embodimentof the present invention is illustrated at FIG. 23 and includes an inputshaft 512 to which rotational driving force is input from the drivingshaft of an engine. The input shaft 512 includes a first section 512Aand a terminal section 512B with an input sun gear 514 integrally formedon the input shaft 512 between the first section 512A and the terminalsection 512B.

The speed change control shaft 516 of a predetermined length isrotatably and coaxially mounted on the first section 512A of the inputshaft 512, as illustrated at FIG. 23. The speed change control shaft 516includes the carrier 518 positioned at the first end 516A and with aplurality of splines 516S formed at the second end 516A' of the speedchange control shaft 516 to engage the coaxial splined hub 558S of theturbine 558 to enable the speed change control shaft 516 to be rotatedsimultaneously with the turbine 558 of the speed change controllingsystem 550. Bushings 516B, 516B' are used to ensure that the input shaft512 and the speed change control shaft 516 can independently rotate.

Carrier 520 has a coaxial bore formed therethrough to rotatably receivethe terminal section 512B of the input shaft. Bearing 520B is used toensure that the carrier 520 can freely rotate about the terminal section512B of the input shaft. The plurality of locking pins 522 interlink andsecure the two carriers 518, 520 together to ensure simultaneousrotation of the carriers 518, 520 about the input shaft. A plurality ofplanetary gears 524 are used with each locking pin 522P rotatablyreceiving a planetary gear 524G. Each planetary gear is meshed with theinput sun gear 514. A bearing 524B may be used to mount each planetarygear on each of the plurality of locking pins 522 to ensure rotation ofthe planetary gear about its respective locking pin. The output ringgear 530, which has a coaxial bore 526 formed therein to rotatablyreceive the terminal section 512B of the input shaft, terminates in theoutput shaft 528. The output ring gear meshes with the outside of eachof the plurality of planetary gears 524. Bearing 526B is insertedbetween the bore 526 and the terminal section 512B so that the outputring gear 530 can rotate freely about the input shaft 512.

The composite planetary gear set of the speed change system such assystem 510 as described above, is a basic or fundamental instrument forchanging the engine torque according to the present invention. Andbecause the gears of the planetary gear set are in a constant state ofbeing meshed, it transmits a more powerful force to the output shaft528.

Speed change Controlling system 550

The speed change controlling system 550 is the same as that of the speedchange controlling system 180 described in the second embodiment.However, different reference numbers are used to separate thisembodiment from the second embodiment.

As shown in FIG. 23, the disk cover 552 is secured to the first section512A of the input shaft 512. The input shaft 512 passes through themiddle of the cover 552. A splined hub 552S is coaxially formed in thecover 552 which meshes with the splines 512S formed in the input shaft512 so that the cover 552 can be rotated integrally with the input shaft512. The cover 552 is connected to the impeller 556 by a weld or a dogclutch at the periphery of the cover 552 so that the cover rotatesintegrally with the impeller 556. An optimum number of fluid outlets 554are formed through the cover 552 to enable the flow of fluidtherethrough.

To secure the turbine 558 to the end 516A' of the speed change controlshaft 516 splines 516S are formed on the speed change control shaft 516to receive the coaxial splined hub 558S formed in the turbine 558 toenable the turbine 558 and the speed change control shaft 516 to rotatesimultaneously. Bushings 516B, 516B' are used to ensure that the inputshaft 512 independently rotates relative to the speed change controlshaft 516 coaxially positioned thereon.

The impeller 556 and the turbine 558 are installed facing each other insuch a manner so as to be spaced apart only a very small distance butsufficiently apart to permit rotation without direct mechanicalengagement, i.e. contact. A stator 560 is positioned between theimpeller 556 and the turbine 558 and secured to a one-way bearing 561having a coaxial formed splined hub 560S for receiving the splines 562Sformed on the fixed shaft 562.

Bushings 562B, 562B' are used to ensure that the speed change controlshaft 516 rotates independently relative to the fixed shaft 562. Bearing556B secures the fixed shaft 562 to the impeller 556 to permitindependent rotation of the impeller 556. A fluid passageway 565 isformed in the fixed shaft 562, with the fluid passageway 565 terminatingbetween the stator 560 and the impeller 556 to permit circulation of thefluid of the speed change controlling system 550, as illustrated in FIG.23. A fluid inlet 564 is operatively secured to the fluid passageway565.

The housing 566, for containing the fluid, is secured to the fixed shaft562 by means of a splined hub 566S formed therein which receives thesplines 562S' of the fixed shaft 562. The housing encloses the speedchange control system 550 and includes a fluid outlet 568 formed thereinto enable fluid to pass therethrough. A bearing 566B is used so that theinput shaft 512 can rotates freely within the housing 566. A fluid-seal566C is also used to prevent leakage of the fluid. The housing 566 issecured against rotation by an external fixing means.

To achieve reverse rotation of the output shaft relative the rotation ofthe input shaft, a reverse rotation brake means 570 is used to apply abraking force to the speed change control shaft 516 so that the speedchange control shaft 516 and the carriers 518, 520 of the speed changesystem 510 can be slowed and stopped by inhibiting the rotation of thespeed change control shaft 516.

The characteristics and advantages of the speed change controllingsystem 550 simply constructed as above are that part of the rotationalpower of the engine controls the rotation of the turbine 558 through theimpeller 556, that is, the rotation is always controlled at a speedchange point at which the driving force of the engine and the runningresistance of the output shaft 528 always reach an equilibrium state.

The power transmission process and the speed change status of thepresent embodiment constructed as above are explained below in theneutral, forward rotation and reverse rotation states.

IV-1. Neutral state (FIG. 24): Output ring gear 530 is stopped.##STR18##

In the neutral state the driving force of the engine is not output tothe output shaft 528 and the transmission idles as shown in FIG. 24.That is, when the output shaft 528 is in a stationary state due to aload, a portion of driving force of the engine through the input shaft512 rotates the impeller 556 of the speed change controlling system 550in direction "A". As the blades of the impeller 556 rotate together withthe fluid, the fluid discharged from the blades strikes the blades ofthe turbine 558 which tends to increase the rotation of the turbine 558in direction "A". However, when the load of the output shaft 528 islarge and the engine idles at a low speed, the torque is relativelysmall, then the fluid discharged from the impeller 556 cannot produce aforce sufficient to increase the rotation of the turbine 558 andtherefore the turbine slips. Therefore, the power input to the input sungear 514 cannot decrease the rotation of the planetary gears 524 whichare rotating in direction "B" and the transmission idles.

Reviewing the rotation of the turbine 558 which slips in direction "A",the turbine 558 rotates, not by the force of fluid discharged from theimpeller 556, but by the characteristics of the planetary gear set andthe influence (load) of the output ring gear 530 through the speedchange control shaft 516.

As described above, when the engine idles at a low speed, the force ofthe fluid discharged from the impeller 556 does not produce sufficientforce to cause an increase in the speed of the turbine 558 forcontrolling the rotation of the carriers 518, 520. Therefore thecarriers 518, 520 and the planetary gears idle in the direction "A" and"B", respectively, which results in the neutral state.

IV-2. Forward rotation state (FIG. 25): Until the rotation ratio of theinput shaft and the output shaft becomes 1:1 ##STR19##

In the forward rotation state the output shaft 528, which was stopped inthe neutral state as described above, the rotation is initiated andgradually increases until the rotation of the output shaft becomes sameas that of the input shaft (rotation ratio 1:1).

When rotational speed of the engine is gradually increased from that ofthe neutral state, the rotational speed of the impeller 556 increaseswhich increases the force of fluid being discharged by the impellerblades. The increasing fluid force increases the rotation of the turbine558 and gradually increases the rotation of the output shaft 528 as therotation of the turbine 558 increases.

That is, if the rotational output of the engine is increased, the forceof the fluid discharged by the impeller is increased which increases therotation of the turbine which was rotating in direction "A" into thespeed change point at which the rotational force of the turbine isequilibrated with the load of the output shaft 528. Therefore, therotation of the carriers 518, 520, which were rotating in direction*A"A" through the speed change shaft 516 integrally connected with theturbine 558, increases gradually over the neutral state, and therotation of planetary gears 524 meshed with the input sun gear 514,about their respective axes in direction "B", decreases gradually andfinally stops. At this time, the gradual decrease of the rotation of theplanetary gears 524 in direction "B" is proportional to the gradualincrease of in their revolutions with the carriers 518, 520. Therotation of the output ring gear 530, meshed with the planetary gears524, increases in proportion to the decrease of the rotation of theplanetary gears about their own axes. When the rotation of the planetarygears 524 about their axes is decreased and finally stops, the drivingforce of the engine and the running resistance of the output shaft 528constitutes a state of equilibrium. That is, in this state all the gearsof the speed change system 510 form a rotating body which rotatestogether with the carriers 518, 520.

As described above, the characteristic of the present embodiment is thatthe transmission always reaches a state of equilibrium according to thedriving force of the engine of the running vehicle and the load of theoutput shaft 528 which can vary at any time, by simple construction andmethod.

IV-3. Reverse rotation state (FIG. 26): Turbine 558 and carriers 518,520 are stopped ##STR20##

In the reverse rotation state the output shaft 528 rotates in adirection opposite to that of the input sun gear 514. A brake force Pb1applied by the reverse rotation brake means 570 installed on the speedchange control shaft 516 during the above described neutral state, thenthe carriers 518, 520 and the turbine 558 which were rotating indirection "A", stop and the output ring gear 530 rotates in a directionopposite to that of the input sun gear 514. That is, as the rotation ofthe carriers 518, 520, which were rotating in direction "A" in theneutral state, gradually decreases because of the brake force Pb1, therotation of the planetary gears 524 in direction "B" is increased andtherefore the output ring gear 530 rotates in direction "B" which isopposite to that of the input shaft 512.

A description of the sixth embodiment of the stepless automatic variabletransmission of the present invention combines the speed change system610, overdrive system 660 and speed change controlling system 680 withreference to FIGS. 27-32 follows.

In this embodiment, the overdrive system is located between the speedchange system 610 and the speed change controlling system 680.

Speed change system 610

The stepless automatic variable transmission 600 of the sixth embodimentof the present invention, as shown in FIGS. 27 and 28, includes an inputshaft 612 to which rotational driving force is input from the drivingshaft of an engine. The input shaft 612 consists of a first section612A, a second section 612B, and a terminal section 612C.

The input carrier 614 and an input sun gear 616 are integrally formedwith the input shaft 612 between the first section 612A and the secondsection 612B, and between the second section 612B and the terminalsection 612C, respectively. The speed change shaft 618, of apredetermined length, is rotatably and coaxially mounted on the secondsection 612B of the input shaft 612. The reverse rotation sun gear 620is integrally formed at the first end 618A' of the speed change shaft618, and a control ring gear 622 is integrally formed at the second end618A of the speed change shaft 618. Bearings 620B, 620B' are used sothat the input shaft 612 and the speed change shaft 618 canindependently rotate. The output shaft 626 includes a coaxial bore 624formed therein. Bearing 624B is installed in the bore 624 to ensure thatthe output shaft 626 and the input shaft 612 rotate independently. Theoutput shaft 626 includes an output sun gear 628 positioned at the firstend 626A of the output shaft 626.

The carrier 630 is rotatably positioned on the speed change shaft 618near the reverse rotation sun gear 620. Bearing 630B is used to ensurethat the speed change shaft 618 and the carrier 630 can independentlyrotate. Disk carrier 634 having a tube shaft boss 632 is rotatablypositioned on the output shaft 626 near the output sun gear 628. Bearing634B is used to ensure that the output shaft 626 and the carrier 634 canindependently rotate. The plurality of locking pins 636 interlink andsecure each of the carriers 630, 634 together, as see FIG. 27, in orderto enable the two carriers 630, 634 to simultaneously rotate about theshaft 618 and the output shaft 626, respectively.

A plurality of reverse rotation planetary gears 640, input planetarygears 638 and output planetary gear 642, are used. A reverse rotationplanetary gear 640G, input planetary gear 638G and output planetary gear642G, which are integrally formed, are rotatably positioned on eachlocking pin 636P of the plurality of locking pins 636. The reverserotation planetary gear 640 is spaced apart 638A from the inputplanetary gear 638 and the input planetary gear 638 is spaced apart638A' from the output planetary gear 642 which may be integrally formedand coaxially mounted on each locking pin 636P using bearings 640B, 642Bto ensure simultaneous rotation about the locking pin, as illustrated atFIG. 28. The input planetary gear 638, the reverse rotation planetarygear 640 and the output planetary gear 642 are meshed with the input sungear 616, the reverse rotation sun gear 620 and the output sun gear 628,respectively.

Two sets are used with a set consisting of a locking pin 636P andcomposite planetary gears 638G, 640g, 642G, however, the number of suchsets is not limited.

Overdrive system 660

The control shaft 668 is coaxially and rotatably mounted on the inputshaft 612 proximate the input carrier 614 which is secured between thefirst section 612A and the second section 612B of the input shaft, assee FIG. 28. The control shaft 668 includes a first end 668A with acontrol sun gear 670 positioned thereat and a second end 668A' with aplurality of splines 672S formed thereat. Bearings 670B, 672B are usedto ensure that the input shaft 612 and the control shaft 668 canindependently rotate. The carrier 662 is rotatably positioned on thecontrol shaft 668 near the control sun gear 670 with a bearing 662B toensure that the carrier 662 and the control shaft 668 can independentlyrotate. A plurality of locking pins 664 interlink and secure the twocarriers 614, 662 together in order that carriers 614, 662simultaneously rotate together, with the control sun gear 670 in thecenter, as see FIG. 27.

A plurality of overdrive planetary gears 666 are used with eachoverdrive planetary gear 666G being rotatably mounted via bearing 666Bon each locking pin 664P so as to enable independent rotation. Eachoverdrive planetary gear 666G is meshed with the control sun gear 670and the control ring gear 622, respectively.

Speed change controlling system 680

The construction of the speed change controlling system utilizes theprinciple of the action and reaction to maintain equilibrium.

A control blade member 684 having a plurality of control blades 686extending radially therefrom and including a coaxial splined hub 682Sformed therein is used. The splined hub 682S engages the plurality ofsplines 672S formed in the control shaft 668, which is rotatably andcoaxially mounted on the first section 612A of the input shaft 612, toenable the control shaft 668 and the control blade member 684 tosimultaneously rotate about the input shaft 612. Each control blade 686Bof the plurality of control blades 686 extends radially at a constantangle so as to possess grater rotational resistance. Each control blade686B preferably includes a connecting portion 687 which has less surfacearea relative to the blade, as illustrated at FIG. 28. The housing 692is rotatably secured to the input shaft 612 and to the control shaft668, via bearings 692B, 692B', in order to operatively enclose thecontrol blade member 684 to prevent fluid contained in the housing fromleaking out. Fluid-seals 694, 694' can also be used, for example. Thehousing further includes an internal surface 693 spaced apart from theplurality of control blades radially extending from the splined hub682S, with a plurality of resistance plates 690 secured to the internalsurface of the housing such that each resistance plate 690P ispositioned proximate the control blades 686 as see FIG. 28.

The housing 692 is secured against rotation to, for example, the housingof the speed change system 610 or the overdrive system 660. A fluidinlet 696 and a fluid outlet 698 are formed in the housing 692 so thatthe amount of fluid in the housing can be regulated. In use, the housing692 is filled to only about 90% of capacity, and in the state in whichthe automatic speed change is not required, e.g in the neutral, reverserotation, and starting state, the fluid is discharged from the housingby a pump or the like.

The structural characteristics and operating status of the speed changecontrolling system 680 as constructed above are that the variabletransmission by itself can form a new speed change ratio continuously sothat the engine's driving force of the moving vehicle corresponds to theload exerted on the output shaft. That is, the characteristics is thatthe speed change controlling system is constructed as a self-operatedcontrol type which utilizes the rotational force of the object of therotation control.

Before describing the operation, because in the neutral, reverse,overdrive and starting states the transmission is operated at a fixedspeed change ratio, each brake means is used, while under normal drivingconditions after starting, the fluid in the housing is regulated in thespeed change controlling system 680 in order that the automatic speedchange can be made.

Reviewing the operating state, the control blades 686 which areinstalled in the housing 692 of the speed change controlling system 680,rotate and at the same time cause the fluid to be centrifugally forcedagainst the resistance plates 690. Ultimately the fluid is forced backagainst the control blades 686, causing a decrease in the rotation ofthe control blades.

That is, the force which the control blades 686 tend to push out thefluid and force which the resistance plates 690 counterflow the fluidhinder the rotation of the control blades 686.

The rotation of the reverse rotation sun gear 620 increases inproportion to the gradual decrease in the rotation of the control blades686 and therefore the rotation of the output shaft 626 increases. To thecontrary, when the driving force of the engine is constant and the loadof the output shaft 626 is large, the rotation of the control blades isgradually increased, but the rotation of the output shaft 626 decreases.

As described above, before the change of the load exerted on the outputshaft has influence on the input shaft 612, the speed change ratiocorresponding to the load is continuously determined and therefore theequilibrium state in which the driving force and the load are consistentcan be made.

To change the speed of the output shaft the brake means for applyingrotational braking force is used at each step.

First, the forward rotation brake means 659, which also includes aone-way clutch to enable rotation in only one rotational direction, isinstalled on the tube shaft boss 632 of the carrier 634 to apply thebrake force to the carrier 634 in the low speed state. The overdrivebrake means 679 is installed on the control shaft 668 to control thecontrol sun gear 670 in the overdrive state. The reverse rotation brakemeans 699 is installed on the speed change shaft 618 to control thereverse rotation sun gear 620 in the reverse rotation state.

Although the brake means are illustrated as being installed on the tubeshaft boss, the speed change shaft or the control shaft, the position ofthe installation or the construction can vary as appreciated by oneskilled in the art. Although a oneway clutch is used in the forwardrotation brake means 659 to eliminate the inconvenience of releasing thebrake force again after applying the brake force at the time of speedchange and to prevent the reverse direction rotation of the carriers630, 634, other means may be used to accomplished this purpose.

A description of the power transmission procedure and speed variationconditions of this embodiment as constructed above is set forth belowwith the speed variation conditions classified into a natural, forwardrotation, high speed and reverse rotation states.

Here, the rotational force received by the input shaft 612 istransmitted in two paths. In one path the rotational force istransmitted to the input carrier 614 of the overdrive system 660, and inthe second path the rotational force is transmitted to the input sungear 616 of the speed change system 610. For the convenience ofexplanation, the procedure is described according to each path the poweris transmitted. ##STR21##

In the neutral state the driving force of the engine is not output tothe output shaft 626 and the transmission idles as shown in FIG. 29.That is, if the rotational force from the driving shaft of the engine isinput with a load applied on the output shaft 626, then the input shaft612 rotates and the input carrier 614 of the overdrive system 660integrally formed on the input shaft is rotated in direct "A". As theinput carrier 614 is rotated, the overdrive planetary gears 666 arerotated about each locking pin 664P, of the plurality of locking pins664, in direction A1 which is the same as that of the input carrier 614.The control ring gear 622, meshed with the overdrive planetary gears666, is rotated in direction A2 which is the same as that of the inputcarrier 614. Also the control sun gear 670 meshed with overdriveplanetary gears 666 and the control blades 686 integrally formed withthe control sun gear 670, idles in direction A3 which is the same asthat of the input carrier 614.

Here, reviewing the rotational direction of each gear in the overdrivesystem 660, all the gears rotate in the same direction as that of theinput shaft 612 since the input carrier 614 is rotated concurrently withinput shaft, the rotational force of each of the respective overdriveplanetary gear 666G about its own axis is small, and the revolutionaryforce of carriers 614, 662 is large. The control blades 686 of the speedchange controlling system 680 idle. That is, the control blades 686 donot receive more resistance in rotation thereof because the housing 692of the speed change controlling system is not filled with the fluid asdescribed above.

Next, simultaneously with the rotation of the input carrier 614according to the rotation of the input shaft, the input sun gear 616 ofthe speed change system 610 is rotated in direction "A" As the input sungear 616 is rotated, the input planetary gears 638P meshed with theinput sun gear 616, are rotated about the locking pin 636P in direction"B" opposite to the rotational direction of the input sun-gear 616.Therefore, the reverse rotation planetary gear 640G and the outputplanetary gears 642G, which are integrally formed with the inputplanetary gears 638G, rotate in direction "B" which is the same as thatof the input planetary gears 638. However, because the output sun gear628, meshed with the plurality of output planetary gears 642, isstationary due to the load, the plurality of output planetary gears 642revolve around the output sun gear 628 while at the same time, rotatingabout their respective axes. Therefore carriers 630, 634 are rotated indirection C1, which is opposite to the rotational direction of the inputshaft 612. The reverse rotation sun gear 620 meshed with each of thereverse rotation planetary gears 640G which are rotated in direction "B"opposite to the rotational rotation of the input shaft 612. Here, thereverse rotation sun gear 620 and the control ring gear 622 are rotatedintegrally.

Because the output shaft 626 is stationary due to the load, therotational force through the input shaft 612 is not transmitted to theoutput shaft and makes the control blades 686, the reverse rotation sungear 620, the control ring gear 622 and the carriers 630, 634 idle,which results in the neutral state.

V-2. Forward rotation state (FIGS. 30A and 30B) ##STR22##

In the forward rotation low speed state the rotation of the output shaft626 is gradually increased from the neutral state. If in the abovedescribed neutral state a brake force Pcl is applied by the forwardrotation brake means 659 installed on the tube shaft boss 632 of thecarrier 634, the rotation of the carriers 630, 634, which were rotatingin a direction C1 opposite to that of the input shaft 612, decreases andstops. Therefore the rotation of output shaft 626 gradually increases inproportion to the decrease of the rotation of the carriers 630, 634.

FIG. 30A illustrates the transmission of rotational power asaccomplished by the operation of only the speed change system 610. Asthe input sun gear 616 is rotated, the input planetary gears 638 meshedwith it are rotated in the same direction "B", which is as in theneutral state, and the rotation about the locking pin 636P decreasesuntil the carriers 630, 634 stop. Therefore, the rotation of each of theoutput planetary gears 642G integrally formed with the input planetarygears 638 about their own axes also decreases.

As the rotational force of the output planetary gears 642 becomesgreater than the revolving force, the output sun gear 628 meshed withthe output planetary gears 642 and the output shaft 626 integrallyformed with it are rotated in direction D1 which is the same as that ofthe input shaft 612. In this speed change procedure, the output shaft626 is rotated at a fixed speed change ratio according to given teethratio when the carriers 630, 634 stop.

Thereafter the fluid is drawn into the speed change controlling system680. In this procedure, the rotation is automatically controlled by thecontrol blades 686 of the speed change controlling system 680 accordingto the load exerted on the output shaft 626 and such controlledrotational force increases the rotation of the control ring gear 622 inthe rotational direction of the input shaft, and also increases therotation of the reverse rotation sun gear 620 integrally formed with thecontrol ring gear 622 in the same direction.

FIG. 30B illustrates the state where the rotation of the output shaft isincreasing over the state illustrated at FIG. 30A. In this case, therotation of the carriers 630, 634 is increased in direction E1, which isthe same as that of the input shaft 612. As the rotation of the reverserotation sun gear 620 continuously increases, the rotational directionof the reverse rotation planetary gear 640G, which is meshed with thereverse rotation sun gear 620 and is rotating in direction "B" oppositeto that of the input shaft, changes into direction "A", which is thesame as that of the input shaft 612. Just as the reverse rotationplanetary gears 640G which change rotational direction from direction"B" into direction "A" same as that of the input shaft, the revolvingforce of the carriers 630, 634 increases and the input planetary gears638 and the output planetary gears 642 change rotational direction androtate in the same direction "A" as that of the input shaft 612.

In this state, the rotation of the control blades 686 in the speedchange controlling system 680 decreases due to the resistance force ofthe resistance plates 690 and therefore the rotation of the output shaftis gradually increased.

At this time each planetary gear 638G, 640G, 642G revolves with thecarriers 630, 634 while at the same time rotating about its respectivelocking pin 636P. The driving force which is transmitted to the inputplanetary gears 638 through the input sun gear 616 of the speed changesystem 610 and the driving force which is transmitted to the reverserotation planetary gears 640 through the input carrier 614 of theoverdrive system 660 join together at the output planetary gears 642 tofurther increase the rotation of the output sun gear 628 meshed with theoutput planetary gears and the output shaft 626 integrally formed withthe output sun gear in the direction D1 which is the same as that of theinput shaft 612.

In this state, in proportion to the increase of the rotation of theoutput shaft 626, the rotation of each planetary gear 638G, 640G, 642Gabout its own axis is decreased and the revolution thereof with thecarriers 630, 634 is increased.

For reference, as the revolution of each planetary gear 638G, 640G, 642Grevolving together with the carriers 630, 634 is increased, the outputsun gear 628 meshed with the output planetary gears 642 cannot berotated in a direction opposite to that of the input shaft 612 but isrotated in the same direction D1 as the input shaft. This occurs becausethe influence of the increasing revolutionary force becomes larger thanthe influence of the rotational force of the output planetary gears 642.Because the influence of the increasing revolutionary force of thereverse rotation planetary gears 640 becomes relatively larger than thatof the rotational force, it promotes the rotation of the reverserotation sun gear 620 meshed with the reverse rotation planetary gearsin the same direction as the input shaft, and owing to this the rotationof the control ring gear 622 decreases the rotation of the control sungear 670.

Therefore, because the rotation of the control blades 686 integrallyformed with the control sun gear 670 is decreased, a new speed changeratio which can correspond with the load variation of the output shaft626 by only small resistance force of the control blades is determined,and this speed change ratio constitutes the optimum equilibrium state inwhich the engine driving force and the resistance of moving theautomobile is equal.

Reviewing the rotational state, as the rotation of the output shaft 626is increased, the revolving force of each planetary gear 638G, 640G,642G revolving together with the carriers is increased, the rotationthereof about its own axis is decreased, and when the rotation of theoutput shaft is same as that of the input shaft 612, all the elementsform a rotating body with the input and output shaft in the center. V-3.Overdrive state (FIG. 31) ##STR23##

In the overdrive state a further acceleration from the forward rotationstate described above takes place If a brake force PC2 is applied by theoverdrive brake means 679 installed on the control shaft 668, therotation of the control blades and the control sun gear 670 stops andthe output shaft rotates in an overdrive state.

In this state, the rotational force passing through the input shaft 612is transmitted along two paths. In one path the rotational force istransmitted to the reverse rotation planetary gears 640 by passingthrough the input shaft 612, the input carrier 614 of the overdrivesystem 660, the overdrive planetary gears 666, the control ring gear622, and the reverse rotation sun gear 620. In the other path therotational force is transmitted to the input planetary gears 638 bypassing through the input shaft 612 and the input sun gear 616 of thespeed change system 610.

The rotational forces, after passing through these two paths, jointogether at the carriers 630, 634 and the output planetary gears 642,and increase the rotation of the output sun gear 628 and the outputshaft 626 over that of the input shaft 612. At this time, because therevolutions input from the control ring gear 622 of the overdrive system660 are greater and the revolutions input from the input sun gear 616are less, in order to transmitted it to the output sun gear 628 byuniting the different revolutions from the two paths into one, therotation of the carriers 630, 634 is increased more than that of theinput shaft 612.

In this state, the rotational direction of all the gears and carriers issame as that of the input shaft 612, and each planetary gear 638G, 640G,642G is rotated about its own axis by a difference in numbers ofrevolutions input from the two paths.

V-4. Reverse rotation state (FIG. 32) ##STR24##

A description of the overdrive system 660 and the speed changecontrolling system 680 is omitted because in the reverse state theoutput shaft 626 is rotated at a given fixed ratio by a compulsory speedchange method which does not require an automatic speed change.

In the reverse rotation state the output shaft 626 rotates in adirection opposite to that of the input sun gear 616. Upon applying abrake force PC3 by the reverse rotation brake means 699 to the speedchange shaft 618 in the neutral state, then the reverse rotation sungear 620, which was idling in direction A2 which is the same as therotational direction as the input shaft 612, slows and stops and theoutput shaft 626 is rotated in direction F1 which is opposite to that ofthe input sun gear 616.

In operation as the input sun gear 616 is rotated, the input planetarygears 638 meshed with it are rotated in the same direction "B" as in theneutral state. Both the reverse planetary gears 640 and the outputplanetary gears 642 rotate in direction "B". However, as the reverserotation sun gear 620 slows and stops, the reverse rotation planetarygears 640 meshed with it revolve around the reverse rotation sun gear620.

Therefore, as the revolutions of the reverse rotation planetary gears640 increases, the carriers 630, 634 which were rotating in direction C1in the neutral state, rotate more rapidly. At the same time, the inputplanetary gears 638 and the output planetary gears 642, which areintegral with the reverse rotation planetary gears 640G, also rotateabout their own axes and increase their revolutions together with thecarriers 630, 634. Therefore, as the revolutions of the output planetarygears 642 revolving together with the carriers increases, the output sungear 628 meshed with it cannot rotate in the same direction as the inputshaft 612 but is rotated in direction F1 which is opposite to that ofthe input shaft because the influence of the revolving force of theoutput planetary gears 642 becomes relatively greater than that of therotational force.

Note that the relative magnitude between the revolving force and therotational force varies according to the change in the number of teethof each meshed gear.

A description of the seventh embodiment of the stepless automaticvariable transmission of the present invention combines the speed changesystem 610, overdrive system 760 and speed change controlling system 780with reference to FIGS. 33-38 follows.

In the stepless automatic variable transmission 700 of the seventhembodiment of the present invention only the overdrive system 760 andthe speed change controlling system 780 are constructed different thansimilar systems in the sixth embodiment. The construction of the speedchange system 610 is same as that in the sixth embodiment and is omittedhereat for the sake of brevity. The overdrive system and the speedchange controlling system is described using the same reference numeralsfor similar parts. The brake means which applies a braking force toperform the speed change at each stage is the same as that of the sixthembodiment except for the fact that the position of installation isdifferent due to the change in the construction of the overdrive system,therefore only a brief description is given. The operation of theoverdrive system and the speed change controlling system is the same asthat of the sixth embodiment, therefore only a brief description isgiven.

The speed change controlling system 780 utilizes an impeller and aturbine of a conventional torque converter but does not utilize either astator or a fluid pump. Thus, the description of the system 780 is basedon the construction of a conventional converter with certain changes inthe names of the functioning elements.

The impeller (pump) disk of the torque converter is referred to as aresistance plate, the impeller blades are referred to as resistanceblades, the turbine disk is referred to as a control plate, and turbineblades are referred to as control blades. The housing encloses theresistance plate, the control plate and control blades, prevents fluidleakage from the housing and includes a fluid outlet and fluid inlet.

The arrangement of the functioning elements is different than that ofthe conventional converter. That is, the resistance plate is installednear the engine and the control plate is installed near the speed changesystem, with the spacing between them being the same as in theconventional device, as see FIG. 34. The relative positions of theoverdrive system and the speed change controlling system are same as forthe sixth embodiment, as compare FIG. 27 and FIG. 33.

Below is given a detailed description of the overdrive system 760 andthe speed change controlling system 780 of the seventh embodiment 700according to the present invention in conjunction with accompanyingdrawings.

Overdrive system 760

As shown in FIGS. 33 and 34, the overdrive sun gear 714 is integrallyformed on the input shaft 612 between the first section 612A and thesecond section 612B. The speed change shaft 618 of a predeterminedlength is rotatably and coaxially mounted on the second section 612B ofthe input shaft 612. The control sun gear 722 is integrally formed atthe second end 618A of the speed change shaft 618, and the reverserotation sun gear 620 of the speed change system 610 is integrallyformed at the first end 618A' of the speed change shaft 618. Bearings620B', 722B are used to enable the input shaft 612 and the speed changeshaft 618 to rotate independently.

The carrier 764, including a tube shaft boss 762, is rotatably andcoaxially positioned on the speed change shaft 618 near the control sungear 722 with bearing 764B being used to enable the carrier 764 torotate independently about the speed change shaft 618. The control shaft768 having a first end 768A and a second end 768C with the carrier 766integrally formed at the first end 768A thereof and being rotatably andcoaxially mounted on the first section 612A of the input shaft to enableindependent rotation about the input shaft. Bearings 768B, 768B' areused to enable the control shaft 768 and carrier 766 to independentlyrotate about the input shaft 612 together. The control shaft 768terminates with a plurality of splines 768S formed thereat to engage thecoaxial splined hub 782S of the control plate 782 to enable the controlplate 782 to rotate simultaneously with the control shaft 768.

A plurality of locking pins 770 interlink and secure together the twocarriers 764, 766 to enable simultaneous rotation. A plurality ofoverdrive planetary gears 772 and a plurality of control planetary gears774 are used. An overdrive planetary gear 772G and a control planetarygear 774G are spaced apart 772A relative to each other, are integrallyformed and rotatably, via bearings 772B, 774B, and coaxially positionedon a locking pin 770P. While FIG. 34 shows the overdrive planetary gear772G and the control planetary gear 774G as being the same size, theirrespective size can differ, as appreciated by one skilled in the art.The overdrive planetary gear 772G and the control planetary gear 774Gare meshed with the overdrive sun gear 714 and the control sun gear 722,respectively.

To engage the overdrive system, the overdrive brake means 679 applies arotational brake force to the tube shaft boss 762 of the carrier 764.

Speed change controlling system 780,

The control shaft 768 terminates with a plurality of splines 768S formedthereat to securely engage the coaxial splined hub 782S of the controlplate 782 to enable the control plate 782 to rotate simultaneously withthe control shaft 768. The control plate 782 includes a plurality ofcontrol blades 784 extending radially therefrom at a angle so as toincrease rotational resistance.

The resistance plate 790, having a plurality of resistance blades 792extending radially therefrom in the same shape as the control blades784, is rotatably and coaxially mounted on the input shaft 612. Onemethod of securing the resistance plate 790 to the input shaft 612 is tocoaxially and rotatably mount a fixed shaft 788 of predetermined lengthon to the input shaft and to coaxially securely mount the resistanceplate thereto.

The housing 794 encloses the control plate 782 and resistance plate 790to contain and prevent fluid from leaking out, as see FIG. 34. Thehousing 794 includes a splined hub 794S to receive the plurality ofsplines 786 formed onto the fixed shaft. Bearing 794B is used to enablethe input shaft 612 to rotate independently from the fixed shaft 788.Also, a fluid-seal 794A is used proximate the bearing 794B to preventfluid from leaking out of the housing during use. In like manner, thehousing is rotatably secured to the control shaft 768 by the use ofbearing 794B' and a fluid-seal 794A' is used to prevent fluid fromleaking out of the housing during use.

The plurality of control blades 784 are positioned across from theplurality of resistance blades 792, such that they are spaced apart avery small distance in order to ensure there is no frictional engagementbetween the blades.

The housing 794 which fixes the resistance plate 790 is secured to theoutside, for example, the housing of the speed change system. Fluidinlet 796 and fluid outlet 798 are formed in the housing 794 so that theamount of fluid in the housing can be regulated. For example, in use,the housing is 90% filled with fluid. However, where the automatic speedchange is not required, e.g. in the neutral, reverse rotation, andstarting state, the fluid is discharged into a reservoir.

In view of the fact that the power transmission procedure and theprinciple of the speed change state of the seventh embodiment of thestepless automatic variable transmission are similar to those of thesixth embodiment, only a brief description follows.

VI-1. Neutral state (FIG. 35) ##STR25##

Since the operation and the rotational direction of the speed changesystem 610 in the neutral state are same as in the neutral state of thesixth embodiment and, therefore, a further description is not considerednecessary. A description of the overdrive system 760 follows. In theneutral state the driving force of the engine is not output to theoutput shaft 626 and the transmission idles as shown at FIG. 35. Thatis, if the rotational force from the driving shaft of the engine isinput where a load is applied on the output shaft 626, the input shaft612 is rotated and the overdrive sun gear of the overdrive system 760integrally formed on the input shaft is rotated in direction "A". Aplurality of overdrive planetary gears 772, of control planetary gears774 and locking pins 770 are used in this embodiment. As the overdrivesun gear 714 is rotated, each of the overdrive planetary gears 772Gmeshes with it and each of the control planetary gears 774G, integrallyformed with the overdrive planetary gears, rotates about each lockingpin 770P, respectively, in a direction A5 which is the same as that ofthe overdrive sun gear 714. The control sun gear 722, meshed with thecontrol planetary gears 774, is rotated in direction A6, which is thesame as that of the overdrive sun gear 714. Because the output shaft 626is stationary, the carriers 764, 766 are rotated more rapidly indirection A7, and therefore the control shaft 768, integrally formedwith the carriers and the control blades 784, are rotated in the samedirection A7.

Here, reviewing the rotational direction of each gear in the overdrivesystem 760, all the gears are rotated in the same direction as that ofthe input shaft 612. The reason is that the revolutionary force of theoverdrive planetary gear revolving together with the carriers 764, 766is greater than the rotational force of that about its own axis. Thecontrol blades 784 of the speed change controlling system 780 idle. Thisis because the control blades 784 do not receive more rotationalresistance because the housing 794 of the speed change controllingsystem is not filled with the fluid as described in the sixthembodiment.

VI-2. Forward rotation state (FIGS. 36A and 36B) ##STR26##

The application of the brake force Pd1 to achieve forward rotation inthe low speed state is same as that of in the sixth embodiment, as seeFIG. 36A. A description of the procedure from when the fluid is suckedor drawn into the speed change controlling system 780 is set forth blow.

From the time when the fluid is sucked or drawn into the housing 794 ofthe speed change controlling system 780, the rotation is automaticallycontrolled by the control blades 784 according to the load exerted onthe output shaft 626 and such controlled rotational force increases therotation of the control sun gear 722 in the rotational direction ofinput shaft, and also increases the rotation of the reverse rotation sungear 620 of the speed change system 610 integrally formed with thecontrol sun gear 722. As shown at FIG. 36B, the rotation of the carriers630, 634 is increased in direction E1, which is the same as that of theinput shaft 612. As the rotation of the reverse rotation sun gear 620continuously increases, the rotational direction of the reverse rotationplanetary gear 640G, which is meshed with the reverse rotation sun gear620 and is rotating in direction "B" opposite to that of the inputshaft, changes into direction "A", which is the same as that of theinput shaft 612. In this state, the rotation of the control blades 784in the speed change controlling system 780 decreases due to theresistance force of the resistance blades 792 and therefore the rotationof the output shaft is gradually increased.

Just as the reverse rotation planetary gears 640G which changerotational direction from direction "B" into direction "A" the revolvingforce of the carriers 630, 634 increases and the input planetary gears638 and the output planetary gears 642 also change rotational directionand rotate in the same direction "A" as that of the input shaft 612. Atthis time each planetary gear 638G, 640G, 642G revolves with thecarriers 630, 634 while at the same time rotating about each locking pin636P. The driving force which is transmitted to the input planetarygears 638 through the input sun gear 616 of the speed change system 610and the driving force which is transmitted to the reverse rotationplanetary gears 640 through the overdrive planetary gears 772 of theoverdrive system 760 loin at the output planetary gears 642 and furtherincrease the rotation of the output sun gear 628 meshed with the outputplanetary gears and the output shaft 626 integrally formed with theoutput sun gear in direction D1, which is the same as that of the inputshaft 612.

In this state, in proportion to the increase of the rotation of theoutput shaft 626, the rotation of each planetary gear 638G, 640G, 642Gabout its own axis decreases and the revolution thereof with thecarriers 630, 634 increases.

Reviewing the rotational direction in this state, the control blades784, all the gears and carriers 764, 766 in the overdrive system 760,and all the gears in the speed change system 610 are rotating in thesame direction as the input shaft 612.

VI-3. Overdrive state (FIG. 37) ##STR27##

In the overdrive state a further acceleration from the forward rotationstate described above takes place. Application of a brake force Pd2 bythe overdrive brake means 679 to the tube shaft boss 762 of the carrier764, causes the rotation of the control blades 784 of the speed changecontrolling system 780 and the carriers 764, 766 of the overdrive system760 to slow and stop and the output shaft 626 rotates in the overdrivestate.

In this state, the rotational force passing through the input shaft 612is transmitted along two paths. In one path the rotational force rotatesthe overdrive sun gear 714 of the overdrive system 760 by passingthrough the input shaft 612, rotates the overdrive planetary gears 772in a direction opposite to that of the input shaft, and rotates thecontrol planetary gears 774 integrally formed with the overdriveplanetary gears 772 in a direction opposite to that of the input shaft,rotates the control sun gear 722 meshed with the control planetary gears774 and the reverse rotation sun gear 620 integrally formed with thecontrol sun gear in the same direction as that of the input shaft, andis transmitted to the reverse rotation planetary gears 640 meshed withthe reverse rotation sun gear 620. In the other path the rotationalforce rotates the input sun gear 616 by passing through the input shaft612 and is transmitted to the input planetary gears 638.

The rotational forces, after passing along these two paths, join at thecarriers 630, 634 and the output planetary gears 642, and increase therotation of the output sun gear 628 and the output shaft 626 greaterthan that of the input shaft 612. At this time, because the revolutionsinput from the control sun gear 722 of the overdrive system 760 isgreater and the revolutions input from the input sun gear 616 of thespeed change system 610 is less, in order to transmit it to the outputsun gear 628 by uniting the different revolutions from the two paths toone, the rotation of the carriers 630, 634 is increased to more than therotational speed of the input shaft 612, which results in the overdrivestate in which the rotation of the output shaft 626 is increased so asto be greater than that of the input shaft 612.

VI-4. Reverse rotation state (FIG. 38) ##STR28##

This state is same as the reverse rotation state at FIG. 32 of the sixthembodiment, and therefore a description thereof is omitted. Forreference, note that the carriers and each gear in the speed changecontrolling system 780 and the overdrive system 760 rotate in the samedirection as that of the input shaft 612.

On the one hand, an appropriate adjustment of the numbers of teeth ofthe gears used in the present invention according to the desired purposecan obtain the required numbers of revolutions of the output shaft. Forreference, Table 1 represents the number of teeth of each gear in thefirst embodiment, Table 2 represents the number of revolutions of thespeed change system, e.g. the number of revolutions of the output ringgear per 1 revolution of the input shaft according to Table 1, and Table3 represents the number of revolutions of each part in the operatingstate of Table 2. Likewise, Table 4 refers to the number of teeth ofeach gear in the third embodiment, and table 5 shows the number ofrevolutions of the output shaft (per 1 revolution of the input shaft)according to the number of teeth in Table 4. For convenience, each gearin the overdrive system represents only one example of the number ofteeth. However, as appreciate by those skilled in the art the number ofteeth can vary.

Table 6 represents the number of revolutions of each part (per 1revolution of the input shaft) in the operating state of Table 5. Inlike manner, Table 7 represents the number of teeth of each gear in thesixth embodiment, and Table 8 represents the number of revolutions ofthe output shaft (per 1 revolution of the input shaft) according toTable 7. Likewise, Table 9 refers to the number of teeth of each gear inthe seventh embodiment, and Table 10 shows the number of revolutions ofthe output shaft (per 1 revolution of the input shaft) according toTable 9.

                                      TABLE 1                                     __________________________________________________________________________    (First embodiment)                                                            Speed change system (10)               Overdrive system (50)                                                Medium                                                                             Output                                                                            Overdrive                              Input  Input Control                                                                             Output                                                                              Control                                                                            speed                                                                              ring                                                                              sun   Planetary                                                                          Terminal                    sun    differential                                                                        differential                                                                        differential                                                                        sun  ring gear                                                                              gear  gear ring                        gear (14)                                                                            gear (34)                                                                           gear (36)                                                                           gear (38)                                                                           gear (22)                                                                          gear (44)                                                                          (46)                                                                              (56)  (68) gear (74)                   __________________________________________________________________________    1 21   30    18    30    33   81   81  27    27   81                          2 21   33    20    33    34   87   87  27    27   81                          3 24   36    21    36    39   96   96  27    27   81                          __________________________________________________________________________

                  TABLE 2                                                         ______________________________________                                        Low speed state                                                                           Medium speed state                                                                          Reverse rotation state                              (Carriers 26,                                                                             (Medium speed ring                                                                          (Control sun gear 22                                28 stop)    gear 44 stops)                                                                              stops)                                              ______________________________________                                        1   0.2593      0.412         -0.198                                          2   0.24        0.39          -0.21                                           3   0.25        0.4           -0.17                                           ______________________________________                                         * "-" indicates the opposite direction to the input shaft.               

                                      TABLE 3                                     __________________________________________________________________________                     Low speed state     Reverse rotation state                                    (Carriers 26, 28                                                                        Medium speed state                                                                      (Control sun gear                        Neutral state    stop)     (Medium speed ring                                                                      22 stops)                                       Medium    Medium    gear 44 stops)  Medium                                    speed                                                                              Control                                                                            speed                                                                              Control   Control    speed                                     ring sun  ring sun       sun        ring                                 Carriers                                                                           gear gear gear gear Carriers                                                                           gear Carriers                                                                            gear                                 (26, 28)                                                                           (44) (22) (44) (22) (26, 28)                                                                           (22) (26, 28)                                                                            (44)                               __________________________________________________________________________    1 -0.35                                                                              -0.7 0.165                                                                              -0.2593                                                                             0.382                                                                             0.21 0.51 -0.62 -1.04                              2 -0.32                                                                              -0.64                                                                              0.175                                                                              -0.24                                                                              0.37 0.19 0.496                                                                              -0.598                                                                              -0.984                             3 -0.33                                                                              -0.66                                                                              0.145                                                                              -0.25                                                                              0.36 0.33 0.487                                                                              -0.56 -0.95                              __________________________________________________________________________     * "-" indicates the opposite direction to the input shaft                     * Indication about the high speed state is not made because the rotation      ratio of the input shaft and output shaft is 1:1.                        

                                      TABLE 4                                     __________________________________________________________________________    (Third embodiment)                                                                               Medium      Medium                                           Input                                                                             Input  Control                                                                             speed  Control                                                                            speed Output                                     sun differential                                                                         differential                                                                        differential                                                                         sun  sun   ring                                                                              Link                                                                              Overdrive                                                                           Transmitting                                                                          Output               gear                                                                              gear   gear  gear   gear gear  gear                                                                              gear                                                                              gear  gear    gear                 (314)                                                                             (340)  (344) (346)  (318)                                                                              (322) (352)                                                                             (358)                                                                             (368) (370)   (378)              __________________________________________________________________________    1 20  30     20    30     30   20    80  30  24    27      27                 2 21  33     21    34     33   20    87  30  24    27      27                 3 25  35     25    39     35   21    95  30  24    27      27                 __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________    Low speed state     Medium speed state                                                                              Reverse rotation state                  (Control sun gear   (Medium speed sun (Carriers 332, 334                      318 stops)          gear 322 stops)   stop)                                     Rotation of output                                                                     Rotation of output                                                                     Rotation of output                                                                     Rotation of output                                                                     Rotation of output                                                                     Rotation of output               ring gear 352                                                                          shaft 376                                                                              ring gear 352                                                                          shaft 376                                                                              ring gear 352                                                                          shaft 376                      __________________________________________________________________________    1 0.25     0.31     0.5      0.63     -0.25    -0.31                          2 0.241    0.30     0.54     0.68     -0.241   -0.30                          3 0.263    0.33     0.56     0.7      -0.263   -0.33                          __________________________________________________________________________     * The rotation of the output ring gear 352 is the output rotation of the      speed change system 310.                                                      * When the rotation of the speed change system 310 is overdrived in the       overdrive system 360, the rotation of the final output shaft 376 is           obtained.                                                                

                                      TABLE 6                                     __________________________________________________________________________    Neutral state     Low speed state                                                                         Medium speed state                                                                      Reverse rotation state                               Medium    Medium    Control                                                                            Control                                                                             Medium                                    Control                                                                            speed     speed     sun  sun   speed                                Carriers                                                                           gear sun gear                                                                           Carriers                                                                           sun gear                                                                           Carriers                                                                           gear gear  sun gear                             (332, 334)                                                                         (318)                                                                              (322)                                                                              (332, 334)                                                                         (322)                                                                              (332, 334)                                                                         (318)                                                                              (318) (322)                             __________________________________________________________________________    1  0.2  -0.33                                                                              -1   0.4  -0.5 0.6  0.33 -0.66 -1.5                              2  0.194                                                                              -0.32                                                                              -1.175                                                                             0.389                                                                              -0.6 0.63 0.39 -0.64 -1.7                              3  0.208                                                                               -0.357                                                                            -1.262                                                                             0.416                                                                               -0.66                                                                             0.65 0.4   -0.714                                                                              -1.857                           __________________________________________________________________________

                                      TABLE 7                                     __________________________________________________________________________    (Sixth embodiment)                                                                              Speed change system (610)                                   Overdrive system (660)     Reverse                                                                            Reverse                                         Overdrive                                                                           Control                                                                            Control                                                                            Input                                                                             Input                                                                              rotation                                                                           rotation                                                                           Output                                                                             Output                                planetary                                                                           ring sun  sun planetary                                                                          planetary                                                                          sun  planetary                                                                          sun                                   gear  gear gear gear                                                                              gear gear gear gear gear                                  (666) (622)                                                                              (670)                                                                              (616)                                                                             (638)                                                                              (640)                                                                              (620)                                                                              (642)                                                                              (628)                               __________________________________________________________________________    1 27    81   27   24  36   26   34   18   42                                  2 25    80   30   25  35   24   36   20   40                                  3 30    84   24   21  29   21   29   18   32                                  __________________________________________________________________________

                  TABLE 8                                                         ______________________________________                                        (Fixed speed change ratio)                                                        Low speed state          Reverse                                              Carriers 630,                                                                             Overdrive state                                                                            rotation state                                       634 of the  Control shaft 668                                                                          Speed change shaft                                   speed change                                                                              of overdrive 618 of the speed                                     system 610 stop                                                                           system 660 stops                                                                           change system 610 stops                          ______________________________________                                        1   0.285 →                                                                            1.485        -0.457                                           2   0.357 →                                                                            1.460        -0.227                                           3   0.407 →                                                                            1.356        -0.246                                           ______________________________________                                    

                                      TABLE 9                                     __________________________________________________________________________    (Seventh embodiment)                                                                                  Speed change system (610)                             Overdrive system (760)           Reverse                                                                            Reverse                                   Overdrive                                                                           Overdrive                                                                           Control                                                                            Control                                                                            Input                                                                             Input                                                                              rotation                                                                           rotation                                                                           Output                                                                             Output                          sun   Planetary                                                                           planetary                                                                          sun  sun planetary                                                                          planetary                                                                          sun  planetary                                                                          sun                             gear  gear  gear gear gear                                                                              gear gear gear gear gear                            (714) (772) (774)                                                                              (722)                                                                              (616)                                                                             (638)                                                                              (640)                                                                              (620)                                                                              (642)                                                                              (628)                         __________________________________________________________________________    1 34    26    30   30   21  32   22   31   18   35                            2 33    24    27   30   24  30   21   33   18   36                            3 35    25    31   29   24  34   24   34   20   38                            __________________________________________________________________________

                  TABLE 10                                                        ______________________________________                                        (Fixed speed change ratio)                                                        Low speed state          Reverse                                              Carriers 630,                                                                             Overdrive state                                                                            rotation state                                       634 of the  Carriers 764, 766                                                                          Speed change shaft                                   speed change                                                                              of the overdrive                                                                           618 of the speed                                     system 610 stop                                                                           system 760 stops                                                                           change system 610 stops                          ______________________________________                                        1   0.337 →                                                                            1.381        -0.24                                            2    0.4 →                                                                             1.290        -0.22                                            3    0.49 →                                                                            1.621        -0.25                                            ______________________________________                                    

As described above, the advantages of the present invention include astepless automatic variable transmission of a simple construction whichcan be operated in a stepless automatic speed change method which cantransmit the power to the output shaft with an optimum speed changeratio by obtaining an equilibrium of the driving force and the loadbefore a change of the load exerted on the output shaft gives aninfluence on the input shaft under a condition in which all the gearsare in a constant state of engagement without the need for changinggears by disengaging and engaging the gears when the power of the engineis to be changed in its speed and output to the output shaft via aninput shaft. In the other method the fixed speed change ratios arecontinuously modified such that a maximum engine braking effect isobtained and transmits it to the output shaft when running in amountainous area or on an icy road or when a rapid starting is required,or by combining the two methods.

It is obvious that the stepless automatic variable transmission of thepresent invention is not limited to the present embodiments but can beapplied to all the apparatuses which can change a speed of a drivingforce and output it to the output shaft in all the vehicles andindustrial machines based on the purpose of the present invention, andthat various revisions and alterations can be made in the scope of thepresent invention.

For example, it is described that in the first and second embodiments anapparatus constructed by combining the speed change controlling system80, 180 and the overdrive system 50 is connected to the speed changecontrol shaft 20 of the speed change system 10, 110 and is alsoconnected to the output ring gear 46 to overdrive. It is described thatin the third and fourth embodiments an apparatus constructed bycombining the speed change controlling system 380 and the overdrivesystem 360 is connected to the control shaft 316 of the speed changesystem 310, 410 and is also connected to the output ring gear 352 tooverdrive, and likewise it is also described that in the sixth and theseventh embodiments an apparatus constructed by combining the speedchange controlling system 680, 780 and the overdrive system 660, 760 isconnected to the speed change shaft 618 of the speed change system 610,however, it is of course that the present invention is not limited tothe above embodiments, and the same function can be performed even whenthe above described combination apparatus is connected to varioustransmissions (stepless automatic variable transmissions previouslyfiled by the present applicant).

In addition, same function can be performed even when the number and thepositions of teeth of the control sun gear 318 and the medium speed sungear 322 in the third embodiment are changed and the medium speedcontrol shaft 320 is connected to the speed change controlling system380, and same function can be performed even when the speed changecontrolling system 680 of the sixth embodiment and the speed changecontrolling system 780 of the seventh embodiment are changed to eachother.

Furthermore, a simple pressurized brake lining braking method is used asa method for applying a frictional brake force with a brake means in theembodiments of the present invention however, the construction,embodying method and installation position of such apparatus can bevaried in various ways, and a variety of circuit constructions forautomatic control utilizing an electric, electromagnetic brake andhydraulic and pneumatic pressure can be used for such apparatus, andthis does not limit the scope of the present invention.

And the speed change controlling system which is an apparatus using afluid for speed change control is used in the embodiments of the presentinvention, however, the construction, embodying method and installationposition of such apparatus can be varied in various ways, and a fluidcoupling, variable motor, powder clutch, powder coupling, electric andelectromagnetic clutch, etc. can be used for such apparatus, and thisdoes not limit the scope of the present invention.

Although this invention has been described in its preferred form with acertain degree of particularity, it is appreciated by those skilled inthe art that the present disclosure of the preferred form has been madeonly by way of example and that numerous changes in the details of theconstruction, combination and arrangement of parts may be resorted towithout departing from the spirit and scope of the invention. Thereference numerals in the claims are used to more clearly illustrate theinvention when considered with the figures and are not intended to limitthe scope of the claims or imply that the scope of the claims is limitedto the exact means so referred to by the respective numeral.

What is claimed is:
 1. A speed change system and speed controllingsystem, comprising:an input shaft 512 for receiving rotational inputwith a first section 512A and a terminal section 512B and an input sungear 514 integrally formed between said first section 512A and saidterminal section 512B of said input shaft to enable simultaneousrotation with said input shaft; a speed change control shaft 516 with afirst end 516A and a second end 516A' coaxially and rotatably mounted onsaid input shaft 512 to enable independent rotation about said inputshaft and a plurality of splines 516S formed at the second end 516A' ofthe speed change control shaft 516; a carrier 518 integrally formed atsaid first end 516A of said speed change control shaft 516 to enablesimultaneous rotation with said speed change control shaft 516; acarrier 520 rotatably mounted on said terminal section 512B of saidinput shaft to enable independent rotation about said terminal section512B; a plurality of locking pins 522 with each said locking pin 522Psecured to and interlinking said carriers 518, 520 to enablesimultaneous rotation of said carriers about said speed change controlshaft and said input shaft, respectively; a plurality of planetary gears524 with each said planetary gear 524G being rotatably mounted on eachsaid locking pin 522P and being meshed with said input sun gear 514; anoutput ring gear 530 coaxially and rotatably mounted on said terminalsection 512B of said input shaft, and being meshed with each saidplanetary gear 524G and terminating in an output shaft 528; a fixedshaft 562 coaxially and rotatably mounted on said speed change controlshaft 516 to enable said speed change control shaft 516 to rotateindependently of said fixed shaft and further including a fluidpassageway 565 formed therein with said fluid passageway in fluidcommunication with a fluid inlet 564; a cover 552 secured to said firstsection 512A of said input shaft to enable simultaneous rotationtherewith and having a plurality of fluid outlets 554 formedtherethrough; an impeller 556 integrally formed with said cover 552 andbeing rotatably mounted on said fixed shaft 562; a turbine 558operatively positioned opposite said impeller 556 and secured to saidsecond end 516A' of said speed change control shaft 516; a stator 560positioned between said turbine 558 and said impeller 556 and mounted onsaid fixed shaft 562 to permit oneway rotation about said fixed shaft562 and with said fluid passageway 565 terminating between said stator560 and said impeller 556; and a housing 566 for operatively enclosingsaid turbine 558, said impeller 556 and said stator 560, mounted to saidfixed shaft 562 and rotatably secured to said input shaft 512 to permitindependent rotation of said input shaft 512 and having a fluid outlet568 formed in said housing to enable, in use, fluid to circulatetherethrough and with said housing operatively secured to preventrotation.
 2. The speed changed system and speed controlling system ofclaim 1 further including an overdrive system operatively connectedthereto for increasing rotational output of said output shaft to definea stepless automatic variable transmission.